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The GENTRA User Guide

1. CALL PUT LINE GENTRA returns control to true ENDIF ENDIF IF LSTSWP PSTLSW TRUE LGSWEP ISWEEP ENDIF i SECTION 6 FINISH OF IZ SLAB ELSEIF ISC EQ 6 THEN SECTION 7 FINISH OF SWEEP ELSEIF ISC EQ 7 THEN Test whether the RESREF criterion was met before LSWEEP CALL LASTSW SECTION 8 FINISH OF TIME STEP ELSEIF ISC EQ 8 THEN IF GHFILE 1 4 NE NONE THEN IF NOT STEADY AND NX EQ 1 OR NY EQ 1 OR NZ EQ 1 THEN DO I 1 NTRACK ILOCO IPFSTR 1I IPRSTN IWRT ISTEP EQ 1 VRT ISTEP WRITE LUHIS I4 A 11 1PE13 3 IWRT F ILOCO J J 1 10 ENDDO ENDIF ENDIF IF LG 30 THEN LXU2D LOF XU2D LYV2D LOF YV2D LOC1 LOF C1 IFACE IG 30 CALL TRKDEN LOC1 1 LXU2D LYV2D IFACE ENDIF F GENCAL AND ISTEP EQ LSTEP THEN write GENTRA restart file IF NOT STEADY AND NTRACK GT 0 CALL WRSTRT GENTRA check IF LG 10 THEN RNTRAK REAL NTRACK RESIDL 0 0 ICK 6 IF TSOLVE ICK IF VAPSOL ICK 8 DO 115 IS 1 ICK IRG 50 1S RESIDL RESIDL ABS 15 RG IRG RG 1 E 7 CONTINUE F RESIDL GT 0 2 THEN WRITE BUFF 1 WRITE BUFF 2 1150 50 1IS CHQ IS IS 1 6
2. C ELSEIF IGR EQ 9 THEN SECTION 1 Density of phase 1 DEN1 IF ISC EQ 1 AND QEQ RHO1 GRND THEN LG 30 AND ISTEP GT 1 CALL FN2 DEN1 C1 RG 1 RHO2 RG 1 IF STORE VAPO AND STORE DEN1 AND T STORE JTEM1 OR STORE H1 THEN Ce Gas constant FN2A 8314 0 GMWCON FN2B 8314 0 GMWVAP FN2A LOFVAP LOF VAPO IF STORE JTEM1 LOFTEM LOF JTEM1 IF STORE H1 LOFH1 LOF H1 LOFDEN LOF DEN1 LOFPRE LOF P1 IF STORE VPOR LOFVPO LOF VPOR IF STORE PROPS LOFPRP LOF PROPS DO 9010 J 1 NY DO 9010 I 1 NX JNYIM1 J NY I 1 Is this is blocked cell CALL SUB2R SOLREG 0 0 CHKBLK 1 1 IF STORE VPOR CHKBLK F LOFVPO JNYIM1 IF STORE PROPS SOLREG F LOFPRP JNYIM1 IF SOLREG LT REAL PRINDX AND CHKBLK GT GPOROS THEN on the vapour mass fraction VAPOUR F LOFVAP JNYIM1 Cy Find the local temperature IF STORE 1 THEN CTEMPR F 10 1 ELSEIF STORE H1 THEN ve ieee Currently this is only for constant Cp The user can change it so that Cp will be a function of local C and vapour mass fraction Iteration may be needed for C that purpose CT EMPR TMP1A TMP1B F LOFH1 JUNYI M1 END F
3. ELSEIF INDVAR EQ H1 OR INDVAR EQ JTEM1 AND 1 STORE HEAT THEN CALL FNO VAL HEAT ELSEIF INDVAR EQ VAPO AND STORE MASS THEN CALL FNO VAL MASS ENDIF ENDIF IF NOT STEADY CALL FN25 VAL 1 0 DT ELSE CALL FN1 VAL 0 0 ENDIF ENDIF ENDIF C e C GROUP 19 Special calls to GROUND from EARTH C ELSEIF IGR EQ 19 THEN SECTION 1 START OF TIME STEP IF ISC EQ 1 THEN LGSWEP 0 PSTLSW FALSE IF ISTEP EQ 1 THEN Domain size CALL SUB3R XLASTM XULAST YLASTM YVLAST ZLASTM ZWLAST CELMIN AMIN1 XLASTM FLOAT YLASTM FLOAT NY ZLASTM FLOAT NZ Cy Find the axis CALL FNDAXI ENDIF CALL GENIUS 1 2 C SECTION 2 START OF SWEEP ELSEIF ISC EQ 2 THEN C A Index Of actual be ys IF GFASWP EQ 9999 THEN GFASWP ISWEEP GSWEP1 MAX0 GFASWP GSWEP1 ENDIF Cx SWCD eu LU d supuso Miss Conteh cae Mesue At least two sweeps are needed for one time step LSTSWP ISWEEP GE LSWEEP OR RESMET AND ISWEEP GT 1 GENCAL ISWEEP GE GSWEP1 AND MOD ISWEEP GSWEPF EQ 0 OR GSWEP1 EQ ISWEEP OR LSTSWP Cx D Reset SOULCESE Mid 94959 V vy vw Ne Seal ed ER et SG GENCAL THEN DO 1921 IZZ 1 NZ Ge Setting interphase sources to 0 in the first GENTRA sweep F ISWEEP E
4. G the gas constant for the mixture GASCOS FN2A FN2B VAPOUR om the pressure PRESSR F LOFPRE JUNYIM1 and finally the density LOFDEN JNYIM1 PRESSR PRESSO GASCOS CTEMPR ENDIF 9010 CONTINUE ENDIF SECTION 10 Temperature ELSEIF ISC EQ 10 AND INT TMP1 EQ INT GRND THEN IF STORE JTEM1 AND SOLVE H1 THEN LOFTEM LOF JTEM1 LOFHI LOF H1 86 The GENTRA User Guide 9110 1100 GRO THI TR 211 GENTRA User Guide F STORE VAPO LOFVAP LOF VAPO DO 9110 J 1 NY DO 9110 I 1 NX JINYIM1 J NY I 1 CENTHP F LOFH1 JNYIM1 CTEMPR F LOFTEM JNYIM1 VAPOUR 0 0 IF STORE VAPO VAPOUR F LOFVAP JNYIM1 GCPGAS 1 0 VAPOUR GPROPS 16 CTEMPR GCPCON VAPOUR GPROPS 15 CTEMPR GCPVAP LOFTEM JNYIM1 GPROPS 6 CENTHP GRND1 CONTINUE ENDIF ENDIF ELSEI
5. e SUBROUTINE GENTRA po T C Cs This subroutine is part of the GENTRA particle tracker option Cx of PHOENICS DEREN MEI INCLUDE phoenics d includ satear INCLUDE phoenics d includ grdloc INCLUDE phoenics d includ satgrd INCLUDE phoenics d includ grdbfc INCLUDE phoenics d includ grdear INCLUDE phoenics d includ bfcear INCLUDE phoenics d_includ tracmn INCLUDE phoenics d includ moncom COMMON GENI IDUMI 10 NWHOLE IDUM2 31 NFTOT IDUM3 2 LOOPZ IDUM4 14 COMMON GENCHQ CHQ 8 LOGICAL GENCAL PSTLSW QNE QEQ CHARACTER 80 BUFF 3 NTEGER HEATZ e ISWCNT is a safeguard for the end of time step SAVE GENCAL PSTLSW LGSWEP e C GROUP 1 Run title L F IGR EQ 1 THEN G SECTION 2 GENTRA Preparation F ISC EQ 1 THEN CALL GENPRE GENCAL FALSE PI 3 1415927 IF LG 10 THEN DO 101 IS 1 8 101 15 0 0 ENDIF C SECTION 2 ELSEIF ISC EQ 2 THEN Cs NFTOT is the last used storage in F array IPRTO MAXO NFTOT NBFTOT NF1TOT on 0 location for first particle LASTF IPRTO NOTGXM NOT TSTSWP EQ 12345 0R TSTSWP EQ 10001 0OR TSTSWP LT 0 ENDIF C C GROUP 9 Properties of the medium or media 85 The GENTRA User Guide TR 211 GENTRA User Guide
6. IF GBASE GT 0 0 GPROPS GBASE GMINDX IF PARAMT LE GTSOLD GPROPS 1 0 ELSEIF FUNAME EQ 11 THEN 11 Index of solid fraction formula gprops index of solidification formula paramt local pressure of the continuous phase ELSEIF FUNAME EQ 12 THEN 12 Density of the particle gprops density of particle for liquid only if GTYPE 50 paramt temperature of the particle GPROPS 1000 0 ELSEIF FUNAME EQ 13 THEN 13 Density of the solid phase of the particle gprops density of solid paramt temperature of the solid I ELSE F FUNAME EQ 14 THEN 14 Saturation press of vapour gprops saturation pressure paramt temperature of the liquid Vapour pressure correlation of Bain 1964 Convert from degree Kelvin to Degrees Celcius TCLCIS AMAX1 PARAMT 273 15 1 0 Convert Tsat from degC to degR 97 The GENTRA User Guide C 6894 76 TDI GR 1 8 TCLCIS 492 B D EGR L E 6 712 0 THEN E C TD 0 ELSE Correlation rrelation for T EGR1 73 32642 8 003173 TD 2 ALOG EGR for ZZZ TD state is 12 777 777 IF 52 6 CONS3 0 00 IF CONS3 LT CONS3 50 ELSE CO
7. I 2 Nusselt number 300000020 gprops Nusselt number defval ql set flag paramt particle Reynolds number 95 The GENTRA User Guide 000020 000020 Qo 2C Qu PROPRE RELEE Ca OO One 000040 TR 211 GENTRA User Guide Prandtl number IF STORE H1 THEN PRNDT PRNDTL H1 ELSEIF STORE JTEM1 THEN PRNDT PRNDTL JTEM1 ENDIF IF GRN ABS PRNDT OR PRNDT LT 0 0 PRNDT 0 7 GPROPS 2 0 0 6 SQRT PARAMT PRNDT 0 3333 Froessling Number GPRFFF 1 0 IF VAPSOL AND GPRYVS LT 1 0 THEN GBM GPRYVS GCONGS 1 0 GPRYVS IF GBM GT 1 E 05 GPRFFF ALOG 1 0 GBM GBM ENDIF GPROPS GPRFFF GPROPS ELSEIF FUNAME EQ 3 THEN 3 Thermal conductivity of cont phase without vapour gprops thermal conductivity of pure continuous phase paramt temperature of the continuous phase ELSEIF FUNAME EQ 4 THEN 4 Thermal conductivity of vapour gprops thermal conductivity of vapour paramt particle temperature GPROPS 10 0 9 1E 04 PARAMT 373 0 1 39 1000 0 ELSEIF FUNAME EQ 5 THEN 5 Latent heat of solidification gprops latent heat of solidification paramt particle temperature ELSE F FUNAME EQ 6 THEN 6 Tempe
8. 2 Limitations of GENTRA 1 2 How GENTRA fils in teet 3 About this Guide Una NERA EORR RENE 3 Conventions used in this Guide 2 2 1 5 The GENTRA Input Menu a oen rtu eni 6 About this chapter t E 6 About the GENTRA 6 The GENTRA Main Menu panel eese 7 Help rine 8 Particle ae 9 Physics of current particle 11 Boundary conditions for 19 Numerical controls e eir eremi os gan entero o ER equ RR nnn 25 Input Output controls M 27 Ending the GENTRA Menu 30 The GENTHA Library 30 Using GENTRA PIE arra ciui IDA FORM RE cu 32 32 The
9. be found in the d gentra directory In the tables below the numbers in square brackets indicate the built in default value of the variable Additionally all the GENTRA PIL variables listed in Appendix B are also available in FORTRAN and are automatically assigned the value specified for them in the Q1 file Variables in italics should not be modified by the user C 1 Variables for continuous phase Type Meaning GASPRE GCONGS GCPGAS GEDLIF GEPSIL GKINET GLENGT GSENUL GVFLOW HEAT PRINDX PROPS RESMET REST TEMGAS THRMKC TSOLVE UCDASH UCGASN UPGASN VAPO VCDASH VCGASN VPGASN WCDASH C 2 Variables for particle phase Name Type Meaning O 64 The GENTRA User Guide TR 211 GENTRA User Guide GHCSCC GMCSAA GMCSBB GMCSCC GMINDX GNUSLT GPRYVS GTIMED GTLIQD GTSOLD GVCSAA GVCSBB GVCSCX GVCSCY GVCSCZ GVPART HFGLIQ IUPARN IUPARO IVPARN IVPARO IWPARN IWPARO IXPARN IXPARO IYPARN IYPARO IZPARN IZPARO KILPAR LABPAR Particle ID internal use only LASTF LSTLAB MASS MOMX MOMY MOMZ NPORTS Number of parcels introduced in the current Eulerian time step NTRACK PARNUM PMASSN PMASSO PRVLIN RELVEC Magnitude of relative velocity slip velocity REYNOL ROLIQD ROPARN ROPARO ROSOLD ROTCOO SATPRS 65 The GENTRA User Guide TR 211 GENTRA User Guide SOLFRN SOLFRO SOLIDF SOLLAT SPALD STARAT THRMKV TPARTN TPARTO TUROFF UCPARN UCPA
10. CELL 0 O 0 O O O 1 LSTEP COVAL GENPAT 01 FIXFLU GRND COVAL GENPAT V1 FIXFLU GRND COVAL GENPAT FIXFLU GRND COVAL GENPAT FIXFLU GRND COVAL GENPAT VAPO FIXFLU GRND g For vaporising droplets PATCHes and COVALs are generated for the interphase source of mass as follows PATCH GENMAS CELL 0 0 0 0 O 0 1 LSTEP COVAL GENMAS FIXFLU GRND 33 The GENTRA User Guide TR 211 GENTRA User Guide h Linear relaxation is introduced for the interphase sources through the command RELAX lt var gt LINRLX lt value gt where value is assigned in the menu see Section 2 8 i The call to the GENTRA Ground station is activated by the command NAMGRD GNTR Note that in the provisions c f and h the GENTRA Menu will take into account the dimensionality of the problem and act accordingly 3 6 Transmission to EARTH The GENTRA PIL variables are transmitted to EARTH through the PIL transfer arrays RG LG CG and IG for real logical character and integer variables respectively The transmission takes via the command L GENSET which loads GENTRA Library case G002 The contents of this group do not need to be modified in any way However the RG LG CG or IG variables are being used for the transmission of the user s own data please check this group for clashes with usage by GENTRA The positions in the transfer arrays currently occupied
11. File Edit View Run Options Compile Build Demos Help Dig a Pie Commander Pre processor gt Solver Postprocessor AC3D Geometry Shapemaker Geometry GENTRA track unpacker TECPLOT translator IGES reader Any Start the track unpacker as described above The track unpacker assumes that the name of the global history file has not been changed from the default name ghis The single character identifiers for the names of the individual history and trajectory files must now be specified Typing none will deactivate the production of one or other or both of the file types ji In this example we may want only history files for viewing in AUTOPLOT so type none h to prevent creation of trajectory files and to indicate that the name of the history files are to commence with h The particular tracks for which files are to be produced must now be specified These files can be specified by the individual track number e g 3 4 Combinations of numbers and range up to a maximum of 20 inputs can be accepted e g 1 3 5 7 10 12 14 106 The GENTRA User Guide TR 211 GENTRA User Guide Continuing with the worked example for which five tracks are produced if we want to produce history files for tracks 1 and 4 we can input 1 40r 1 3 4 The resulting history files called h00001 h00003 or h00004 can now be plotted in AUTOPLOT If trajectory files are produced a GENUSE f
12. 0 000000 00 0 000000 00 dir dir di di d di dio dir di di dio dio di dir di di di di di di dir dio di di di di dio dio die div di di div dir die dio di dir di di di dio dio di di di dir di di di di did up 24 Dumps For Restarts 81 The GENTRA User Guide V VV V NM NV OOO QC VV VV V VV VV VN NV V V V VV VV nN IEW P 1 000000 Fl uH EW UP 0 0000001 M M M M BJ BJ BJ BJ BJ BJ BJ BJ BJ BJ BJ BJ BJ BJ BJ BJ BJ BJ TR 211 GENTRA User Guide BJ BJ BJ BJ BJ BJ BJ BJ BJ BJ 82 000000 00 0 000000 00 000000 00 0 000000 00 1 000000 00 1 200000 01 3 000000 01 1 000000 00 2 000000 00 2 000000 01 1 000000 00 1 000000 00 1 000000 00 000000 02 CMPO 0 000000 00 0 000000 00 1 000000E 01 1 000000 00 1 000000 00 1 700000E 01 CMPO BLOCKAGE 199
13. Post processor gt Utilities Figure 4 1 Running the EARTH Solver The usual PHOENICS banner with the CHAM logo will be shown on the screen If GENTRA is to be called during the run the GENTRA banner will also be shown The GENTRA banner contains the version number for your installation of GENTRA GENTRA is called at the beginning of EARTH sweeps The first call will take place at the user selected first GENTRA sweep and subsequent calls with take place according to the user selected GENTRA sweep frequency In each sweep GENTRA will track the particles sequentially Each track is started at its injection position or at the particle position at the end of the previous time step if transient and tracked until an end of track condition is reached End of track events are a The particle has left the domain b The particle has hit an obstacle and has been withdrawn The particle has vaporised completely The particle has been trapped in a stagnation region The tracking of the particle has timed out The particle was killed by the user The end of the Eulerian time step in a transient problem has been reached The tracking of the particle was aborted by GENTRA xw Sem wm mnnn 4 3 Results produced by GENTRA The information provided by GENTRA falls into the following categories a Progress and error information printed on the screen b Information in the RESULT file and c Information i
14. 2 13 Domain Settings E GENTRA Particle inlet conditions Previous menu Note the inlet file name must not be more than 4 characters Inlet data file name GINFIL 0 Browse for file Coordinate system for Positions GCOSYP Currently GRID SYSTEM Coordinate system for Velocities GCOSYV Currently GENTRA CARTESIAN SYSTEM General information PIL Command Figure 2 13 Particle inlet conditions Inlet data file name The inlet data in GENTRA is specified in a table located in an inlet data file The user can select the name of the inlet data file through this option the maximum length of the file name is 4 characters Further information on the contents and format of the inlet data can be found at the end of this sub section The default file name Q1 will be used for the worked example Coordinate system for Positions Option not available in the present version of GENTRA This option allows the specification of inlet co ordinates in the inlet file in either the GENTRA Cartesian system see glossary entry for a definition or in the grid system The distinction is only relevant to cylindrical polar grids since in Cartesian and BFC the GENTRA Cartesian system and the grid system coincide At present the particle positions must be specified in the grid co ordinate system Thus for cylindrical polar grids the co ordinates are specified as z The alignment between the Cartesian and polar grid system
15. Rate of dissipation of turbulence kinetic energy Continuous phase property Q Angular speed of rotation of the co ordinate system E6 13 Continuous phase kinematic viscosity p Density Subscripts p particle v vapour s particle solid phase particle liquid phase c Continuous phase 105 Guide TR 211 GENTRA User Guide The GENTRA User TR 211 GENTRA User Guide Appendix GENTRA Utilities K 1 Plotting Trajectories K1 1 In the Viewer The particle trajectories can be plotted in the Viewer by using the global history file ghis by default as a macro Click on Macro om the hand set or M on the tool bar On the dialog that opens enter the name of the global history file as the Macro file and click OK to run it All the tracks in the file will be read and displayed as Viewer streamlines They can then be turned on and off through the Streamline Management Dialog To plot individual tracks from the history file create a macro file which contains the lines HISTORY READ Filename m n where filename is the name of the history file and n is the number of the track to draw If m is present all tracks in the range m n will be drawn K 1 2 Running UNPACK The track unpacking program UNPACK is run by clicking on Run Utilities GENTRA track unpacker This is required to create individual history files for plotting in AUTOPLOT but is NOT needed for the Viewer PHOENICS VR Editor
16. Save Working files Save As a Save Window Pines Exit On the library dialog click on Browse then open the Option Libraries branch of the library tree The GENTRA libraries are further subdivided as shown in Figure 2 21 30 The GENTRA User Guide TR 211 GENTRA User Guide PHOENICS Input Libraries E x The MIGAL multi grid solver Body fitted co ordinates 5 0 GENTRA particle tracking Lazy and stubborn particles 9 Particles isothermal flow Particles with heattransfer eaaa 9 al E G301 Particle heating in pipe constant gas temperature E G302 st Heat exchanging 1 0 steady cp a bt E G303 Heatexchanging 1 d transient cp a bt Particles with solidification Particles with mass transfer Particles tracking with density calculation LANT Automated FORTRAN GROUND coding Cancel Figure 2 21 The GENTRA Input Library The contents of the Library are listed as Appendix F of this Guide Once the GENTRA Menu session is ended or a library case has been loaded you are ready to execute the calculating program EARTH Chapter 4 explains how to do so You can skip Chapter 3 which gives additional details on data input using PIL if you are a beginner 31 The GENTRA User Guide TR 211 GENTRA User Guide 3 Using GENTRA PIL 3 1 Introduction In addition to using the GENTRA Input Menu you can enter directly in the Q1 file the GENTRA comm
17. The approach of GENTRA is a different one while the continuous phase is treated as above the particles are represented by Lagrangian equations which are integrated to yield the particle trajectory and the particle properties along this trajectory This approach is based on the PSI Cell method of Crowe Sharma and Stock 1977 The standard two phase PHOENICS can therefore simulate particulate flows however the GENTRA approach should be preferred by users who e Need detailed information on the particle trajectory eg because particle impingement on obstacles has to be accurately predicted e Need to simulate accurately particle obstacle interactions such as bouncing sticking or flash vaporisation e Have to consider simultaneously a range of particle sizes temperatures densities etc In these circumstances the two phase approach of PHOENICS would yield an average value for each particle property without any distribution information e Want to avoid numerical diffusion in the particulate phase to which the Eulerian two phase approach is prone and of which the Lagrangian approach of GENTRA is free 1 The GENTRA User Guide TR 211 GENTRA User Guide 1 2 Features of GENTRA The salient features of GENTRA are a In respect of pre processing e Three alternative user interfaces for data input menu command language and FORTRAN e Full on line help facility in the menu e Library of examples and test cases b In resp
18. gprops paramt temp ratur ELSE I IHEN 0 17 heat capacity of pure continuous phase of the gas 17 Solidus temperature 2000000 gprops sat paramt ELSE IF FUNAME EQ 18 THEN phase uration temperature of solidification pressure of cont a 18 Liquidus te mperature 98 The GENTRA User Guide TR 211 GENTRA User Guide gprops saturation temperature of cont phase paramt pressure of cont phase ELSEIF FUNAME EQ 19 THEN S C 19 Particle enthalpy C liquid enthalpy for melt solidif particle e gprops particle enthalpy C liquid enthalpy for melt solid part paramt particle temperature c 265805 0 XPARAM 44 XPARAM PARAMT 273 15 GPROPS 1 80172E 06 1 35627E 06 XPARAM 3 2 56482E 06 XPARAM 2 3 27598E 06 XPARAM C ELSEIF FUNAME EQ 20 THEN C C 20 Vapour saturation temperature as function of pressure C G gprops saturation temperature paramt pressure of the continuous phase G XPARAM ALOG PARAMT 5 0 GPROPS 0 31911 XPARAM 3 3 1032 XPARAM 2 27 287 XPARAM 370 8 C ELSEIF FUNAME EQ 21 THEN C c 21 Cp of s
19. is used in Chapter 2 to indicate comments and instructions addressed to readers who are following the worked example presented in that chapter 5 The GENTRA User Guide TR 211 GENTRA User Guide 2 The GENTRA Input Menu 2 1 About this chapter As noted in Chapter 1 GENTRA is equipped with three user interfaces a A data input menu b The use of PIL commands in the Q1 file c The use of FORTRAN in subroutine GENIUS This chapter explains how to use the input menu for problem specification The use of the GENTRA Input Library of simulations is also discussed at the end of the chapter 2 2 About the GENTRA Menu 2 2 4 What the GENTRA menu does 1 The GENTRA menu allows the user to specify the input data for the disperse phase as choices from a set of hierarchically organised menu panels On line help is available to assist the user in the selection process 2 The GENTRA menu makes automatically all the other provisions needed for the EARTH run Chapter 3 of this Guide details the nature of these provisions for the benefit of the expert user 3 The GENTRA menu writes at the end of the current Q1 file and as PIL commands the results of 1 and 2 above 2 2 2 How to access the GENTRA menu The GENTRA menu is accessed from the Models page of the VR Main Menu which in turn is accessed by clicking on the Menu button of the hand set Full details of the VR Environment are given in TR326 PHOENICS VR Reference Guide Do
20. r sin Xp Uc Vp cos Xp Up sin Xp Vc Up cos Xp Vp sin Xp where R YVLAST OBSTACLES gt 7 See WALLS 7 The term PARCEL is used to refer to a group of particles that are injected at the same time at the same position and with the same properties The parcel is characterised by a MASS FLOW RATE kg s which specifies together with the particle size density and velocity the number of particles in the parcel WALLS AND OBSTACLES Walls and obstacles are defined in GENTRA as in the rest of PHOENICS through face and cell porosities see the CONPOR command in the PHOENICS Reference Manual The level of porosity that will be considered by GENTRA to be an obstruction for the particles can be set by the user see the option POROSITY THRESHOLD in the BOUNDARY CONDITIONS panel 102 The GENTRA User Guide TR 211 GENTRA User Guide Appendix l References 1 1 Quoted in this guide R Clift J R Grace M E Weber 1988 Bubbles Drops and Particles Academic Press New York C T Crowe M P Sharma and D E Stock 1977 The Particle Source In Cell Model for Gas Droplet Flows ASME J Fluids Eng pp 325 332 G M Faeth 1983 Evaporation and Combustion of Sprays Prog Energy Comb Sci Vol 9 pp 1 76 A D Gosman and E loannides 1981 Aspects of Computer Simulation of Liquid fuelled Combustors AIAA 81 0323 AIAA 19th Aerospace Sciences Meeting St Louis Missouri USA D B Spalding 1980
21. 45 The GENTRA User Guide TR 211 GENTRA User Guide The solution of the above variables can be replaced by the simple storage without solution of their values when GENTRA is to track the particles through a frozen flow field 6 3 Lagrangian equations In the simulation of particle behaviour Lagrangian equations are solved which describe the evolution of the position velocity momentum mass and temperature enthalpy of the particle Some combination of these equations is employed for the different types of particle available within GENTRA as detailed in Section 2 5 In the following sub sections descriptions are presented of each of the Lagrangian equations and their relevance to each of the particle types is discussed The method of integration of these equations is explained in Section 6 5 6 3 1 The particle position equation The evolution of the particle position is determined from solution of the following equation _ dt 6 2 where vector is the particle position and Up is the particle velocity Generally the particle velocity is determined from solution of the particle momentum equation as described in Section 6 3 2 However for lazy and stubborn particles the particle velocity is calculated as follows e Lazy particles For lazy particles it is assumed that the particle velocity is identical to the instantaneous continuous phase velocity Up Uc 4Uc where is the time averaged continuou
22. ELSEIF IGENGR EQ 8 THEN F IGENSC EQ 1 THEN C Section 1 Momentum equation C Give constants GVCSAA GVCSCX GVCSCY and GVCSCZ C in the energy equation C C C f Up Ug Up GVCSCX C gw GVCSBB Vg GVCSAA Vp GVCSCY 92 The GENTRA User Guide 3000000000070 30000000020 200000020 TR 211 GENTRA User Guide dt Wp Wg Wp GVCSCZ Up Vp The particle velocity Wp Ug Vg The gas velocity Wg ELSEIF IGENSC EQ 2 THEN Section 2 Energy equation Give constants GHCSAA GHCSBB and GHCSCC in the energy equation ae GHCSBB Tgas GHCSAA Tp GHCSCC M Particle mass T Temperature The default setting A Bl interface heat transfer coefficient Bl Latent heat du to evaporation Disregarding default setting by reseting A Bl and B2 to ELSEIF IGENSC EQ 3 THEN Section 3 Particle mass equation Besse GMCSCC GMCSAA D 2 D Particle diameter ELSEIF IGENSC EQ 4 THEN Section 4 Formulation for solidification d Mass frac of solid GHCSAA d Temper of part ELSEIF IGENSC EQ 5 THEN 7 Section 5 User s equations ENDIF GROUP 9 Particle inlet condition as function of time
23. Figure 2 16 Numerical controls 1st GENTRA sweep This option allows the user to set the first EARTH sweep at which GENTRA will be called It is often a good practice to start the particle tracking when the continuous phase field is developed The selection of values greater than 1 for this option will have that effect This option can also be used to switch off the particle tracking by setting a value greater than the number of PHOENICS sweep LSWEEP If GENTRA is deactivated in this fashion all the GENTRA settings will be retained in the Q1 It will be possible to turn GENTRA on again later If GENTRA is turned off from the Models panel all GENTRA settings are cleared To turn GENTRA back on would involve re setting all the non default values The number of PHOENICS sweeps for the example is LSWEEP 200 choose 190 as the first GENTRA sweep Sweep frequency for GENTRA This option sets the frequency in terms of EARTH sweeps for calls to GENTRA For instance a value of 5 will cause the particle tracking to be effected for those sweeps whose index is a multiple of 5 and greater than or equal to the user specified first GENTRA sweep see option 1 in this menu Values greater than 1 are recommended in conjunction with source relaxation for high particle loadings for the continuous phase is then able to absorb the interphase sources before the next call to GENTRA 25 The GENTRA User Guide TR 211 GENTRA User Guide Since t
24. LET 000000E 00 0 000000 400 0 000000 00 1 000000 00 1 200000E 01 0 000000E 00 LET ER DEFINED OUTLET 0 000000 00 0 000000 00 3 000000E 01 1 000000 00 1 200000 01 0 000000E 00 OUTLET OUTLET 0 000000 00 1 026000 04 1 000000E 03 0 000000 400 0 000000 00 2 000000E 00 WEUN 0 000000 00 1 200000 01 0 000000E 00 1 000000 00 0 000000 00 3 000000E 01 WFUN PLATE VALVEWLL 0 000000 00 1 000000 00 1 000000 01 1 000000 00 0 000000 00 1 700000E 01 VALVEWLL PLATE 0 000000 00 The GENTRA User Guide TR 211 GENTRA User Guide Appendix F Contents of the GENTRA Input Library Overview Group 1 Lazy and stubborn particles Group 2 Particles in isothermal flow Group 3 Particles with heat transfer Group 4 Particles with solidification Group 5 Particles with mass transfer Group 6 Particle tracking with density calculation Loading instructions To load a library case click on File Load from Libraries enter the case number in the Library dialog box and click OK Group 1 Lazy and stubborn particles G704 Tracers in pipe with bend BFC T 3D G706 Beams in reaction turbine BFC T LIBREF 525 Group 2 Particles in isothermal flow G200 Particles in backward facing step STM test G201 Spray dryer BFC T G204 Particles in radial impeller BFC rotating LIBREF 424 G205 Particles through ball valve BFC T LIBREF 534 G207 Rain in sample cup CARTES F
25. Private Change Font Prompt Data File Locations Text File Editor 43 The GENTRA User Guide TR 211 GENTRA User Guide Figure 5 4 Selecting to run a Private EAREXE To run EARTH click on Run Solver Local Solver Earth If private had been selected above the newly built EARTH executable will be run If Prompt had been selected the option of running Private or Public EARTH will be offered PHOENICS VR Editor File Edit View Run Options Compile Build Demos Help Dice EE Commander Pre processor Local Solver Earth Remote Solver Earth Post processor Utilities Figure 5 5 Running the EARTH Solver 44 The GENTRA User Guide TR 211 GENTRA User Guide 6 The GENTRA Equations 6 1 Introduction As pointed out in Chapter 1 GENTRA uses Lagrangian equations for the representation of the particulate phase These equations are listed in the present chapter in which some details of the integration procedure are also given It should be pointed out that users do not need to be acquainted with the contents of this chapter to be able to operate GENTRA successfully the chapter is therefore provided as a reference for users who need to be concerned with the mathematical basis of GENTRA 6 2 The continuous phase equations GENTRA uses for the description of the continuous phase the Eulerian equations built in PHOENICS for single phase flows which have the general
26. such as particle collision and droplet coalescence are not considered RINNER In cylindrical polar grids the PHOENICS variable RINNER which specifies the inner radius of the computational domain must be 0 if GENTRA is used Annular geometries may be represented by specifying RINNER 0 0 and setting the dimension of the first radial cell IY21 to be the required inner radius of the annulus The cells at lY 21 should then be blocked with porosities CONPOR 0 0 CELL 1 NX 1 1 1 NZ TURBULENCE MODULATION Turbulence modulation the effect of the presence of particles on the continuous phase turbulence is not considered TWO PHASE FLOWS GENTRA has not yet been used in conjunction with the Eulerian Eulerian two phase capabilities of PHOENICS ONEPHS F However there is no built in limitation in this respect Note that if used in two phase mode phase 1 variables would be used as representing the continuous phase flow field VOLUME DISPLACEMENT EFFECTS Volume displacement effects ie the volume occupied by the disperse phase and therefore unavailable to the continuous phase are not considered in GENTRA WALLS 60 The GENTRA User Guide TR 211 GENTRA User Guide GENTRA will automatically detect internal and boundary walls however all moving walls will be interpreted as being stationary for the particles 61 The GENTRA User Guide TR 211 GENTRA User Guide Appendix B List of GENTRA PIL variables B 1 In
27. the radius at inlet is 0 15 m it diminishes to a minimum of 0 09 m in front of the ball and the maximum radius is 0 16 m 77 The GENTRA User Guide TR 211 GENTRA User Guide A plug profile of axial velocity is prescribed at the inlet and a fixed pressure condition is employed at outlet Wall qz friction is activated along the boundary of the ball and along the pipe wall A fixed turbulent kinematic viscosity is set to 100 times the laminar value the Reynolds number is of order 1 0 5 ENDDIS ck ck Ck ck Ck Ck CC CC ck ck Ck ck Ck Ck cc ck Ck ck ck Ck ck ko Sk Sk Sk ko ck Sk ck Sk ko ko ko ko ko kx ko ko ko IRUNN 1 LIBREF 1 ck ck ck cc ck Ck CK C Ck Ck Ck cC ck ck Ck ck ck ck ck Ck ck ck ck ck ko Sk Sk ck ko kk kx Sk Group 1 Run Title TEXT FLOW THROUGH A BALL VALVE B534 C CK CC CC CC CC CCCII CC CC CC CC CC CC CK CC C CK C CK C CK C CK CC CC Ck C Group 2 Transience STEADY T CC CC CC CK CC C CC CC CC CC CC CC CC CC CC CK CK C CK C CK C CK C CK C CK Ck CC C Groups 3 4 5 Grid Information Overall number of cells RSET M NX NY NZ tolerance RSE
28. 1 Calculation of the Lagrangian time step At The Lagrangian time step is computed by GENTRA as max 1 2 73 6 26 where to are as follows a is a minimum time step size given by the FORTRAN variable GDTMIN Its default value is 10 0 7 users can re set it in Group 1 of GENIUS b t4 is the minimum cell crossing time divided by the Q1 set variable GLAGTS the minimum number of Lagrangian time steps per cell specified by the user The minimum cell 51 The GENTRA User Guide TR 211 GENTRA User Guide crossing time is estimated by GENTRA for each cell using the minimum cell dimension and the maximum velocity component t2 is the momentum relaxation time If the particle momentum equation is re written as dU de A BUp 6 27 a eee is calculated as where a is a multiplication factor is available through GENIUS as the FORTRAN variable GRTFRL lts default value of 1010 effectively excludes as a criterion in equation 6 26 since it is larger than the others Users wanting to relate the time step At to the momentum relaxation time t2 can reset GRTFRC in Group 1 of GENIUS However this might result in very small time steps for small particles d is the user supplied maximum time step size PIL variable GDTMAX Note that the time step thus computed may be further reduced by GENTRA after the integration of the position
29. 211 GENTRA User Guide Appendix H The GENTRA Glossary The GENTRA Glossary contains a summary of the main terms used in Gentra and its documentation It is also available interactively through the GENTRA Input Menu See Section 2 5 GENIUS GENIUS GENtra Interface for User Sequences is a user accessible FORTRAN module where GENTRA users can insert their own coding sequences to replace and supplement the built in physical laws numerical devices and output options GENTRA Particle tracking software for the PHOENICS flow simulation package GENTRA consists of e The GENTRA Menu a collection of data files to be used with the PHOENICS SATELLITE pre processor The GENTRA GROUND a PHOENICS EARTH GROUND Station which contains the tracking routines GENTRA CARTESIAN SYSTEM GENTRA uses for the integration of the particle equations a Cartesian co ordinate system This system is related to the PHOENICS grid system as follows e For Cartesian grids both systems are identical e For BFC grids the GENTRA Cartesian system is the same Cartesian system used in PHOENICS to define the grid corners e For cylindrical polar grids the relationship between both systems is depicted in the figure The Z axes of the two systems coincide forming a right handed grid in each case The relationships connecting the two co ordinate systems are 101 The GENTRA User Guide TR 211 GENTRA User Guide Xc R r cos Xp Yc R
30. 38 TL Tg This may then be integrated via equation 6 30 For the three types of particles involving heat exchange which are available in the current version of GENTRA ie heat exchanging melting solidifying and vaporizing some terms of the general enthalpy equation are absent For each of these particle types there now follows the form of equation 6 37 which is employed Heat exchanging particles dTp alg m 6 39 mpCp Mp Cp 54 The GENTRA User Guide TR 211 GENTRA User Guide Melting solidifying particles dTp alg di mp Cp Lm Q mp Cp Lm Q 6 40 Vaporising droplets dT aTg Hfg dmp dt aT g e Tet mp 6 41 dt E mp Cp mp Cp 6 5 4 Calculation of sources As the particles traverse each cell exchange of mass momentum and enthalpy may occur For example a particle which is travelling faster than the surrounding fluid will be decelerated and will transfer momentum to that fluid The sources which must be added to the continuous phase transport equations to represent these transfers are as follows Mass transfer T Sm 2g En pp dp9 3 dp 3 6 42 where n denotes values at the end of the Lagrangian time step O denotes values at the start of the Lagrangian time step is the number flowrate of particles for that parcel ie the mass flowrate of that parcel divided by the mass of an individual particle and is the summation over all of the Lagrangi
31. 49 The GENTRA User Guide TR 211 GENTRA User Guide Vaporising droplets dT dm Cp ge 9 Tg Tp 6 19 in which the solidification term is absent 6 4 Submodels 6 4 1 Stochastic turbulence model GENTRA features an optional stochastic turoulence model Gosman and loannides 1981 which accounts for the effects on particle dispersion of the turbulent fluctuations of the continuous phase velocity The model uses as the continuous phase velocity in the drag force term of the momentum equation equation 6 3 a sum of the average velocity Uc and a fluctuating component U c U Uc U c 6 20 where Uc the average velocity is obtained from the Eulerian equations for the continuous phase and U c the fluctuating component is calculated assuming that each component follows a normal distribution with a mean value of 0 0 and a standard deviation of N2K 3 6 21 where is the turbulence kinetic energy The fluctuating component U s is assumed to act over a time interval Ats which is the minimum of a Ate the lifetime of the local eddy which the particle is assumed to be traversing and b Atr the transit time taken for the particle to cross the eddy The eddy lifetime Ate is computed as e where le is the eddy size 3 4 3 2 les EET 6 23 where is the rate of dissipation of turbulence kinetic energy and Cy is a constant in the turbulence model The particle transit time
32. 6 Particle mass fraction calculation This option in the Output control panel provides for the calculation of the particle mass fraction for each cell see Section 6 6 7 It can also be activated by setting STORE PMFR in the Q1 input file 2 10 Ending the GENTRA Menu session The GENTRA Menu session is ended from the GENTRA Main Menu Panel shown in figure 2 2 by clicking on Previous panel This returns control to the normal VR Main menu Choose this option now to finish Click on Top and OK to quit the VR Main Menu Now edit the Q1 file and insert as comments the inlet data for the particles The inlet data must be inserted between the marks lt GENTRA INLET DATA gt and END GENTRA INLET gt in the Q1 file Refer to Section 2 7 1 3 above for instructions and to the Q1 file in Appendix E for an example Copy the settings from Appendix E 2 11 The GENTRA Library GENTRA has a library of ready to run examples and tests To see the contents of the GENTRA Input Library click on File Load from Libraries on the VR Environment top menu File Edit View Run Options Compile Start New case Open Existing case Load from Libraries Reload Working files Load from libraries xi Loading a library case will wipe out your current settings Open file for Editing Enter a case number or select a case from PHOENICS Input Libraries Case number Cancel Browse Figure 2 20 Accessing the Libraries
33. Atr is given by 50 The GENTRA User Guide TR 211 GENTRA User Guide Atr 6 24 6 4 2 Rotating coordinate systems In rotating coordinate systems the particle Up and continuous phase Uc velocities solved for by GENTRA and PHOENICS are the ones relative to the rotating system Coriolis and centrifugal sources must therefore be included in the momentum equations For the particle the extra term in the momentum equation equation 6 3 is Sp mp 2 O Up O O 6 25 where is the angular speed of rotation expressed here as a vector along the axis of rotation Xp is the particle position vector and indicates cross product The rotating co ordinate feature of GENTRA is activated automatically when its PHOENICS counterpart is activated See the entry ROTA in the SATELLITE help dictionary for details on how to activate it and how to specify the axis of rotation and the angular speed Note that the FORTRAN logical variable RoTCOO can be used to deactivate the automatic introduction of this feature See Appendix C for details 6 5 Integration of the equations The numerical integration of the particle equations takes place according to the following sequence a The Lagrangian time step is calculated b The particle is moved c The particle properties at the new position are calculated d The interphase sources are calculated These four steps are dealt with in subsequent subsections 6 5
34. EEP NE LGSWEP NOT LG 11 AND NOTGXM E BUFF 1 A I ENTRA now tracking particles at sweep CALL PR ISW IF W RIT h 2 END F INT_ CH if dbggen then ca call ca endi CALL writl writ8 GI EC IHEN ay K BUFF 1 writli ENCAL is the main particle tracking module late the particle trajectories and the interphase eat and mass at each cel set above THEN LUPRO f PS EL C IF IF NOT LG 11 AND NOTGXM LUPRO NE WRI Ab EL SE 6 E LUPRO A THEN 89 ENCAL AND ENTRA returns control to st double calling in the same sweep EQ 1 AND GI Earth The GENTRA User Guide Earth TR 211 GENTRA User Guide
35. GENTRA User Guide TR 211 GENTRA User Guide 6 2 Thecontinuous phase 45 6 3 Lagrangian 46 6 4 Submodels eee ee ee eee ied e 50 6 5 Integration of the 51 6 6 A Additional nennen nnn 56 Appendix A Known Limitations of GENTRA 59 Appendix B List of GENTRA PIL variables eene 62 Bat Introductlon aise en REPE Ee hee iced 62 B2 iListof variables 5 oerte eie rui roues 62 Appendix C List of GENTRA FORTRAN 64 C 1 Variables for continuous 64 C 2 Variables for particle 64 nEus au 66 Auxiliary nnmnnn 67 Appendix D List of Run Time 70 INtrOGUCTION iin ieee 70 D2 Warning inessages ssc cee tres ccc rere torte 70 D 3 jEHOr essSdges oe Ee
36. GENTRA takes the form of a collection of FORTRAN subroutines which are attached to the PHOENICS flow computing program EARTH GENTRA which solves the equations for the disperse phase is caled by PHOENICS between the sweeps of the computational domain that PHOENICS performs to solve the continuous phase GENTRA then tracks the particles as they move through the computed flow field calculating in the process the interphase interactions i e the transfer of momentum mass enthalpy etc between the phases These interaction terms are after leaving GENTRA incorporated as sources in the continuous phase equations for the next PHOENICS sweep Since the newly introduced sources are likely to alter the flow field used by GENTRA to track the particles in the first instance several iterations of the processes PHOENICS sweep GENTRA tracking will normally be needed to obtain a converged solution For the benefit of readers with some knowledge of the structure of EARTH it will be pointed out here that GENTRA is attached to PHOENICS as a Ground station subroutine that calls in turn all of the modules of GENTRA Most of these modules are delivered in closed i e binary code but the Ground station itself called GENTRA and a special user accessible module GENIUS are provided in open source 1 5 About this Guide 1 5 1 The purpose of this Guide and its intended readership This Guide has been designed to serve both as a user s guide and r
37. Numerical Computation of Multiphase Fluid Flow and Heat Transfer Recent Advances in Numerical Methods in Fluids Ed C Taylor and K Morgan pp 139 167 Relevant CHAM Technical Reports CHAM TR324 Starting with PHOENICS VR CHAM TR326 PHOENICS VR Reference Guide CHAM TR99 The PHOENICS Equations 103 The GENTRA User Guide Appendix J Nomenclature Note Bold typeface indicates vector Ap Particle projected area E6 7 b Buoyancy factor E6 5 Bm Mass transfer number Cp Drag coefficient E6 8 Cp Specific heat capacity Dp Drag function E6 6 F Fr ssling correction for mass transfer Fs Particle solid fraction g CGravitational acceleration vector HfgLatent heat of vaporisation K Turbulence kinetic energy k Thermal conductivity L Latent heat of solidification Mp Mass of a particle Nu Nusselt number Up Ucldp Re Particle Reynolds number Re T Temperature TL Liquidus temperature Ts Solidus temperature W Molecular weight m Solidification index Ate Eddy lifetime E6 10 Atr Eddy crossing time E6 12 Ate Lagrangian time step Particle heat transfer coefficient U Instantaneous continuous phase velocity 104 Guide TR 211 GENTRA User Guide The GENTRA User U c Fluctuating continuous phase velocity Section 6 6 1 Uc Continuous phase velocity Up Particle velocity Xp Particle position YysMass fraction of vapour at droplet surface Mass fraction of vapour in surroundings
38. TIM 93 The GENTRA User Guide TR 211 GENTRA User Guide ELSEIF IGENGR EQ 9 THEN x4 PRVLIN C Ca Section 1 Particle X coordinate IF IGENSC EQ 1 THEN PRVLIN 2 TIM C sess K Section 2 Particle Y coordinate ELSEIF IGENSC EQ 2 THEN PRVLIN 1 0 C Crins Section 3 Particle Z coordinate ELSEIF IGENSC EQ 3 THEN PRVLIN 0 2 C Cds Section 4 Particle U velocity Cartesian components ELSEIF IGENSC EQ 4 THEN PRVLIN 0 1 G d Section 5 Particle V velocity Cartesian component ELSEIF IGENSC EQ 5 THEN PRVLIN 0 1 C or Section 6 Particle W velocity Cartesian component ELSEIF IGENSC EQ 6 THEN PRVLIN 2 0 C Coed Section 7 Particle diameter ELSEIF IGENSC EQ 7 THEN PRVLIN 0 001 C Vs Section 8 Liquid density of particle ELSEIF IGENSC EQ 8 THEN PRVLIN 1000 0 C C Section 9 Mass flow pass particle inlet Nozzle etc ELSEIF IGENSC EQ 9 THEN PRVLIN 0 1 C v ds Section 10 Number of identical particle parcels ELSEIF IGENSC EQ 10 THEN C Cou ese Section 11 Particl
39. applied to locate cell faces which have been blocked by fixing the velocities to zero and which would therefore represent thin plates However users can represent these obstacles by in addition to FIXVALling the velocities to 0 using a porosity of 0 999 and alter accordingly the porosity threshold of GENTRA in the BOUNDARY CONDITIONS section A porosity of 0 999 will then be recognised by GENTRA as an obstacle while leaving the domain virtually unblocked for the diffusion of the continuous phase Fine Grid Embedding GENTRA is not compatible with the use Fine Grid Volume objects GCV and CCM GENTRA is not compatible with the GCV or CCM forms of BFC in single or multi block form OUT OF CORE The out of core device of PHOENICS cannot be used with GENTRA PARABOLIC MODE 59 The GENTRA User Guide TR 211 GENTRA User Guide GENTRA does not work with the parabolic solution procedure of PHOENICS PARAB T PARSOL If GENTRA is used in conjunction with PARSOL Partial Solids treatment inaccurate trajectories near object surfaces may result This is because GENTRA treats all partially blocked cells as completely fluid and will bounce particles from the faces of the first fully blocked cell not the true surface of the object Expected reflection Actual reflection from solid faces Incoming object surface track PARTICLE TO PARTICLE INTERACTIONS Particle to particle effects
40. equations as follows a The particle is not allowed to jump in the current time step beyond the neighbouring cells b for boundary cells i e cells at the boundaries of the computational domain or cells next to internal blockages a particle crossing the cell boundary is placed on the cell boundary by reducing the time step 6 5 2 Moving the particle After computing the time step At the particle is moved by integrating the particle position equations The particle position equation equation 6 2 _ dt P is integrated as X p x9p At 6 28 where n denotes the value at the end of the time step and denotes the value at the beginning of the time step GENTRA integrates the position equations in the GENTRA Cartesian System in cylindrical polar grids equation 6 28 can optionally be integrated in polar co ordinates i e using the radius the angle and the circumferential and radial velocities as variables The FORTRAN logical variable POLTRC see Appendix C accessible from GENIUS controls this option Note however that in order to avoid the singularity at the polar axis 0 GENTRA will always track in Cartesian co ordinates in the centre of the grid IY 1 52 The GENTRA User Guide TR 211 GENTRA User Guide 6 5 3 Integration of momentum mass and enthalpy equation The equations representing the momentum mass and enthalpy of the particles can be represented in the f
41. mass fraction of vapour at the surface of the droplet is calculated thus Wc Yes e 1e prc 1 ye l 6 11 where P is the total pressure of the fluid surrounding the droplet is the partial pressure of the vapour at the surface of the droplet at the saturation conditions defined by the droplet temperature Wc is the molecular weight of the surrounding fluid and Wy isthe molecular weight of the vapour Within GENTRA the mass transfer equation is employed only in the simulation of vaporising droplets 6 3 4 The particle enthalpy equation The temperature of the particle Tp is determined from solution of the particle enthalpy equation In its most general form the particle enthalpy equation may be written dT dfs dm 9 9 Tg Tp 6 12 where Cp is the specific heat capacity of the particle L is the latent heat of solidification Hfg is the latent heat of evaporation fs is the proportion of the solid phase in the particle the solid fraction a isthe heat transfer coefficient between the particle and the surrounding fluid and 48 The GENTRA User Guide TR 211 GENTRA User Guide Tg isthe temperature of the surrounding fluid The specific heat capacity of the particle may be a function of both the temperature and the composition of the particle thus fs Cps Tp 1 fs Tp 6 13 where and represent the specific heats of the solid and liquid p
42. momentum energy mass and solidification equations in this section The particle velocity temperature size etc calculated here will overwrite the corresponding particle property GENIUS Group 9 Particle inlet conditions Whenever a data element in the particle inlet data table described in Section 2 7 1 is replaced by the name of the data item GENTRA will look up the relevant section in this group for the inlet data The inlet data is passed from this section through the variable PRVLIN For example if the inlet data table reads 42 The GENTRA User Guide TR 211 GENTRA User Guide GENTRA INLET DATA XP YP UP _ VP DIAM FRATI 0 1 0 2 UP 1 0 1 2 05 1 2 03 END GENTRA INLET GENIUS Group 9 Section A will be visited for the setting of UP If the user inserts the following coding in Section 4 of this group PRVLIN 3 0 then the x component of the particle velocity will be set to 3 0 m s GI 5 4 The property function GPROPS GPROPS is a function routine for particle properties a full listing of which can be found in Appendix G The arguments of GPROPS are FUNAME PARAMT and DEFVAL FUNAME is the index number of the function eg 4 for the thermal conductivity of the vapour PARAMT is the main parameter of which GPROPS is a function and DEFVAL is the default value for the function If DEFVAL is not a GROUND number GPROPS is set to DEFVAL before returning However if DEFVAL is e
43. on the particles and conversely the effect of the presence of particles on the continuous phase is also considered The data specification and solution procedure for the continuous phase and the particles are carried out by separate modules e PHOENICS is used to specify the data pertaining to the continuous phase This can be done using any of the means available in PHOENICS ie PIL commands a library case or a menu The continuous phase thus specified is then solved by EARTH in the usual way GENTRA is used to specify the data corresponding to the particulate phase This can be done using the GENTRA menu a part of the general PHOENICS VR Main Menu which writes the GENTRA data at the end of the Q1 data file or by using in the Q1 file a subset of PIL variables specific to GENTRA The particulate phase thus specified is then solved by GENTRA Of course the solution procedures for the continuous phase and particles have to interact Details of such interaction can be found in this manual in Section 1 4 2 It should be pointed out that PHOENICS has already a built in two phase capability which uses Eulerian transport equations to represent the two interacting phases Spalding 1980 Similarly to single phase flows these equations are solved by discretising the space into computational cells by integrating the equation over each cell thus obtaining an algebraic equation and by solving the resulting system of algebraic equations
44. parameter NFDIM in the MAIN PROGRAM of EARTH In the GENTRA version of EARTH the MAIN PROGRAM is in the file GENTRA The storage needs for GENTRA are case dependent but the maximum requirement is 13 F array positions per particle Note that recompilation of the file GENTRA and re linking of the EARTH executable is needed after this change Error number 308 No inlet data found Explanation GENTRA could not find any inlet data for particles Remedy Check the name of inlet data file supplied to GENTRA ie the variable GENFIL in the Q1 file If the file name is Q1 then your data should be inserted as comment lines in the Q1 file between the marks lt GENTRA INLET DATA gt and END GENTRA INLET gt 74 The GENTRA User Guide TR 211 GENTRA User Guide Error number 309 GENTRA is not unlocked Explanation The password also called ID string that authorises the EARTH run does not allow the execution of GENTRA Remedy Possible causes are 1 your licence type does not include GENTRA 2 your GENTRA licence has expired 3 you have not inserted the CHAM supplied ID string in the CONFIG file In cases 1 and 2 please contact the Sales Department at CHAM In case 3 please refer to the PHOENICS Installation Manual CHAM TR 110 for instructions and contact CHAM if in doubt Error number 310 Exit symmetry patch type must be EAST WEST NORTH SOUTH HIGH or LOW only Offending PATCH patchnam
45. such as solidification or vaporisation though turbulent dispersion is permitted Lazy particles have no effect on the continuous phase solution On hitting a wall or obstacle the lazy particle will be removed from the domain e Stubborn particles Vpart const Stubborn particles have a constant velocity independent of the continuous phase conditions They therefore behave like beams or rays Stubborn particles do not have a size or a temperature and cannot undergo any physical process such as dispersion by turbulence or solidification or vaporisation They do not exchange momentum with the continuous phase On hitting a wall or obstacle the stubborn particle will be removed from the domain e Stubborn heat transfer Vpart const Stubborn heat transfer particles behave like Stubborn particles except that they can exchange heat with the continuous phase e Stubborn vaporisation Vpart const Stubborn vaporisation particles behave like Stubborn particles except that they can exchange heat and mass with the continuous phase e Isothermal particles Isothermal particles are modelled by Lagrangian equations for the particle position and velocity but not for the particle temperature or size Therefore this type of particle should be selected when no exchange of heat or mass between the continuous and the disperse phase is to be considered On hitting an obstacle an isothermal particle
46. sweep is employed and e a value of 0 sets the source equal to that employed at the previous sweep ie the source does not change Set a relaxation factor of 0 7 2 9 Input Output controls This is the last option of the Main Menu Panel figure 2 2 which controls the input and output data flow of GENTRA When I O controls is selected in the Main Menu Panel the following panel will appear Domain Settings Euer 21 GENTRA I O controls Previous panel Output of histories and trajectories Restart file name 4 chars or less GRSFIL Currently NONE Browse for file Cell residence time calculation GRESTI Currently for particle 0 PIL Command Figure 2 17 Input Output controls 2 9 1 Output of history and trajectory Selection of this option produces the panel of figure 2 18 27 The GENTRA User Guide TR 211 GENTRA User Guide Domain Settings 1 E 2 x GENTRA History and trajectory file Previous panel name of Global history file 4 char GHFILE Currently Jess output for Individual particle Frequency time steps for output GOUTFR Currently 1 PIL Command Figure 2 18 History and trajectory files name of the Global history file Up to 4 characters can be given to the name of the file Specifying NONE results in no global history file being written by the end of the GENTRA EARTH run The global history file contains the results for all of the particle
47. table line is 132 characters Number formatting The formatting of the numbers in the inlet table is free but items of data must be separated with spaces commas or semi colons Error trapping GENTRA will skip those data lines that contain invalid characters such as letter O instead of number zero or that have a different number of data items to that which is required 21 The GENTRA User Guide TR 211 GENTRA User Guide 2 7 1 2 Q1 file as input file By setting the inlet data file name to Q1 the default GENTRA will expect the inlet data table to be in the Q1 file All of the format rules for the inlet data table listed above apply to the Q1 file In addition when the inlet data table is in the Q1 file the following practices must be observed e Inlet data lines must be PIL comments i e they must not start in the first or second column of the Q1 file since they would be treated as commands by the SATELLITE e The inlet data table must be preceded and terminated by two special marks also inserted as PIL comments These marks are lt GENTRA INLET DATA gt and END GENTRA INLET gt respectively e WARNING The maximum length of the inlet data line is 132 characters However users are advised that the maximum length of a Q1 file line for the SATELLITE is 68 characters if the SATELLITE is run after the inlet data has been inserted and following instructions from the user the Q1 file is re written all the dat
48. the same component before the bounce b The velocity component perpendicular to the wall after the bounce is set to the negative of the same component before the bounce multiplied by the restitution coefficient 56 The GENTRA User Guide TR 211 GENTRA User Guide Velocity i Velocity before after 1 1 via Vpb i Vna 1 1 1 1 1 1 1 1 1 Vt restitution coefficient 6 46 Figure 6 1 Particle bouncing 6 6 3 Fluid properties at the particle position The fluid properties at the particle position are computed by GENTRA as follows e For the velocity components in Cartesian and cylindrical polar grids the value is interpolated at the particle position using the values at the two neighbouring nodes e For all the other variables and for the velocity resolutes in BFC cases the fluid properties experienced by the particle are those prevailing at the cell centre The FORTRAN variables which carry the fluid properties experienced by the particle are those listed in Appendix C Users with special needs can modify the values of these variables in GENIUS Group 3 see Section 5 3 3 6 6 4 Particle volume fraction For steady flows STEADY T when STORE PVFR appears in the Q1 file or when the particle index for the calculation of residence time is set to 2 see Section 2 9 3 a particle volume fraction epis computed for each
49. trajectory files The post processing is performed using the program UNPACK which is executed by the command runupk An example of the use of UNPACK is provided in Appendix K This is not needed very often as the Viewer can read the global hisory file directly Users with special output needs can easily create their own output by inserting the appropriate FORTRAN coding in GENIUS Chapter 5 provides further information 37 The GENTRA User Guide TR 211 GENTRA User Guide 5 The GENTRA FORTRAN 5 1 Introduction GENTRA like PHOENICS EARTH has a user accessible area where users can attach their own coding sequences to supplement the built in features This chapter introduces this area 5 2 The structure of GENTRA EARTH The EARTH part of GENTRA is attached to PHOENICS EARTH as a GROUND subroutine While most of the GENTRA EARTH routines are supplied in binary and are not therefore accessible to users some routines are provided in open source see figure 5 1 These are 2 Source files Binary files Earth MAIN Program HS GPROPS Figure 5 1 The GENTRA EARTH structure e GENTRA the Ground Station that attaches GENTRA to EARTH The GENTRA subroutine initialises the GENTRA variables calls the particle tracking modules and then transfers the interphase sources computed by GENTRA to the finite volume equations solved by PHOENICS Users seldom need to introduce changes in this module w
50. 1 001000 1 00 Ij Fl Oo O F for this Group C CK CC CC CC C CC CC CC CC CC CC CC CC CC CC KC CK C CK C CK C CK C CC CK Ck C Ck C CA C Group 12 No Convection and diffusion adjustments PATCHes used for this Group C CK CC CC CK C CC CC CC CC CC CC CC CC CC KC CK C CK C CK C CK C CK Group 13 NL ET NLET VALUE NL ET Pl VALUE NL ET W1 PATCH COVAL COVAL GENPAT GENPAT GENPAT vis 1 W1 LOW ELL Boundary amp Special Sources 2 0 0 0 0 0 1 1 2 000000 03 2 000000 00 F4 E M P 0 0 0 0 0 0 1 1 FIXFLU GRND FIXFLU GRND C CK CC CC CC C CC CC CC CC CC CC CC CC CC CC CK CK C CK C CK C CK C CK C CK CC C C C C Group 14 Downstream Pressure For PARAB Ck Ck c CK C Ck CK Ck C Ck CC c0 Ck Ck Ck Ck Ck cc Ck c ck Ck kk Sk Sk ck ck kk ko ko ko kkk ko ko ko kx oko Group 15 Terminate Sweeps LSWEEP 200 RESFAC 1 000000E 03 KKEKKKKKKKKKKKKKKKKK KKK KKK KK KK ko ck Sk ck ko ko Sk ko ko ko ko ko ko Group 16 Terminate Iterations ck ck ck c Ck Ck Ck CC Sk Ck Ck ck Sk Ck ck kk ck ck ko Sk Sk ck ko ck kx ko ko ko ko ko ko
51. 4 0 002 0 0001 1000 0 1 0 5 0 07 0 00 3 0 0015 1000 0 1 0 5 0 10 0 00 0 5 0 002 1000 0 0 5 0 13 0 00 1 0 001 1500 0 1 0 5 lt END GENTRA INLET gt Wall treatment and rest coefficient if appropriate GWALLC 3 GWREST 7 500000E 01 Porosity threshold GPOROS 0 000000E 00 GENTRA GROUP 3 Numerical controls 1st GENTRA sweep frequency of calls GSWEPl1 190 GSWEPF iL Maximum Lagrangian time step time step size multplier GDTMAX 1 000000E 00 GRTFRC 7 000000E 01 Min of t steps per cell max of t steps timeout GLAGTS 5 GSTEMX 100 GTIMMX 1 000000E 01 80 The GENTRA User Guide TR 211 GENTRA User Guide GENTRA GROUP 4 Output controls Restart file history file and frequency for output GRSFIL NONE GHFILE GHIS GOUTFR 1 The identifier of the individual history and trajectory files GH1STC NONE GITSTC F The first last particles and the interval for writing history and trajectory files NGWSTR 1 NGWEND 5 NGWINT 1 GSWOUT 1 Particle number for residence time calculation GREST 2 L GENSET KKEKKK ck ck KKK oko Group 20 Preliminary Printout EC
52. A menu is available at two levels 1 Help on each menu option can be obtained as explained in Section 2 2 4 above 8 The GENTRA User Guide TR 211 GENTRA User Guide 2 Help items on special topics are available as choices from the menu For instance all the options in the current menu panel are informative ones General information Choose this option to obtain basic information on the use of the GENTRA Input Menu The information contained in this menu entry is covered by several sections in this Guide GENTRA Glossary This entry contains an explanation of the terms used in GENTRA and its documentation The GENTRA Glossary has been included in this Guide as Appendix H Known limitations of GENTRA This entry contains a list of the limitations of GENTRA which are known to the GENTRA Development Team The list is not intended to be exhaustive but the main limitations are presented and where possible alternatives are suggested The information contained in this entry is listed in this Guide as Appendix E Explain run time error number GENTRA EARTH will trap at run time a large number of error conditions and will issue a message to inform the user The message contains an error number and a short explanation of the error After entering an error number and clicking Explain a fuller explanation of the error and if appropriate avoidance instructions will be provided for that error GENTRA errors are classified into Warni
53. Appendix E Listing of the Q1 File for the Example The worked example is based on library case B534 This is a listing of case B534 after passing through the steps described in Chapter 2 TALK T RUN 1 1 CK CK C CK C CK C CK C CK C CK CC C C CA C 01 created by VDI menu Version 3 5 Date 12 11 02 CPVNAM VDI SPPNAM Core p di db dir dir di dir di di di di dir di di dio diro dio dir dir dio di dio dio dio di di dir di dir di dio dio dio di dio dir dio dir dio dio dio dio di diro dir di di dio dio di dir diro di dir Echo DISPLAY USE settings PHOTON USE p use patgeo msg Geometry vec x 1 sh MSG Velocity vectors msg msg Press return to plot pressure contours pause pl x ll i45 004 msg msg Press return to plot streamlines pause clear stream sh x 1 Y posit 3 0 51268 02 0 20453E 04 CR 0 38451E 02 0 19150E 04 CR 0 44859E 02 0 17847E 04 CR 0 76901E 02 0 16740E 04 CR 0 57676E 02 0 15502E 04 CR 0 57676E 02 0 14200E 04 CR 0 51268E 02 0 13548E 04 CR 0 11792E 04 0 12571E 04 t exit use patgeo msg msg Type e to End ENDUSE DISPLAY The incompressible single phase flow of water through a fully open axi symmetric ball valve is solved The pipe work considered is 2 m in length
54. Documentation for PHOENICS TR 211 The GENTRA User Guide Version 2006 Title The GENTRA User Guide CHAM Ref CHAM TR211 Document rev 09 Doc release date 10 October 2006 Software version 5 2006 Responsible author J C Ludwig Other contributors N Fueyo M R Malin Editor J C Ludwig Published by CHAM Confidentiality Classification Unclassified The copyright covers the exclusive rights to reproduction and distribution including reprints photographic reproductions microform or any other reproductions of similar nature and translations No part of this publication may be reproduced stored in a retrieval system or transmitted in any form or by any means electronic electrostatic magnetic tape mechanical photocopying recording or otherwise without permission in writing from the copyright holder Copyright Concentration Heat and Momentum Limited 2006 CHAM Bakery House 40 High Street Wimbledon London SW19 5AU UK Telephone 020 8947 7651 Fax 020 8879 3497 E mail phoenics cham co uk Web site http www cham co uk TR 211 GENTRA User Guide Computer Simulation of fluid flow heat flow chemical reaction and stresses in solids CHAM The GENTRA User Guide TR 211 Contents TE REPETIT TD 1 What GENTRA is and does 2 1 Features of GENTRA etie ieri EU Eu
55. ENTRA User Guide GLHEAS GLIQST GMWCON GMWVAP GNODAL GNUSS GOUTFR GPOLAR GPOROS GPTYPE GRESTI GRSTRT GRTFRC GSOLIN GSOLST GSTEMX GSTOCH GSTPRE GSURPR GSWEP 1 GSWEPF GSWOUT GTISTC GTIMMX GVAPST GWALLC GWREST GXCYCL HNODAL IBODRY IBONCF IGAXI ILOCO INTLEV IPRDIA IPRLAB IPRLIQ IPRNUM IPRSOF IPRSOL IPRSTN IPRTO IPRTEM IPRVEL ITEMIN IVARBL JCOUNT JGAXI JUCRT JVCHT JWCHT KGAXI 68 The GENTRA User Guide TR 211 GENTRA User Guide NGWINT NGWSTR PI POLTRC SUBEDY TCHLIM TCLLIM TCNMAX TCNMIN TCONST TPHLIM TPLLIM TPRMAX TPRMIN A 69 The GENTRA User Guide TR 211 GENTRA User Guide Appendix D List of Run Time Errors D 1 Introduction All the errors reported by GENTRA EARTH at runtime have an identification number This section contains a compilation of the errors with explanations and where appropriate avoidance instructions This list is also available interactively through the menu See Section 2 5 for instructions on how to access it If your version of GENTRA is more recent than the one described in this manual you should also refer to menu for an updated list of errors Section 2 5 of this Guide provides additional information on how errors are classified and handled by GENTRA D 2 Warning messages Warning number 001 Stochastic turbulence model active but no KE or EP Explanation The stochastic model for the dispersion of particles owing to turbulence w
56. F IGR EQ 11 THEN IF LG 30 THEN F INDVAR NE NPHI RETURN LOFXG LOF XG2D LOFYG LOF YG2D LOVAL LOF VAL DO 1100 IX 1 NX DO 1100 IY 1 NY IY IX 1 NY LOVAL I RG 1 XG F 10 YG F 10 F XG 1 63177 YG LT XULAST RG 6 F LOVAL I RHO2 CONTINUE ENDIF UP 13 Boundary conditions and special sources ELSEIF IGR EQ 13 THEN SECTION 12 GENTRA sources IF ISC EQ 12 THEN IF NPATCH 1 6 EQ GENMAS OR NPATCH 1 6 EQ GENPAT F ISWEEP GE GSWEP1 THEN IF NPATCH 1 6 EQ GENMAS THEN Mass source F INDVAR EQ P1 AND STORE MASS THEN CALL FNO VAL MASS CALL GETCOV GENMAS 1 GCOV GVAL IF QNE GCOV FIXFLU THEN GMULT 1 GCOV CALL FN25 VAL GMULT ENDIF ENDIF ELSEIF NPATCH 1 6 EQ GENPAT THEN Other interfacial sources INDVAR EQ U1 AND STORE MOMX THEN CALL FNO VAL ELSEIF INDVAR EQ V1 AND STORE MOMY THEN CALL FNO VAL MOMY ELSEIF INDVAR EQ W1 AND STORE MOMZ THEN CALL FNO VAL 2 87 The GENTRA User Guide TR 211 GENTRA User Guide
57. GENTRA PIL variables are initialised in the GENTRA Library case 20001 This is loaded by the command L G0001 as can be seen in Group 19 of the Q1 listing in Appendix E just before the line GENTR T It is this setting which tells EARTH that GENTRA is active 3 4 GENTRA Groups 1 to 4 GENTRA data This part of the Q1 file see Appendix E for an example carries the problem definition settings It comprises four groups which are the same as those appearing in the main panel of the GENTRA menu see figure 2 2 namely Group 1 Particle physics Group 2 Particle boundary conditions Group 3 Numerical controls Group 4 Input Output controls 32 The GENTRA User Guide TR 211 GENTRA User Guide Settings in these groups are effected by assigning values to the GENTRA PIL variables A list of these variables and where appropriate the acceptable range of values can be found in Appendix B GENTRA Group 2 can also carry optionally the inlet data table See Section 2 7 1 for details 3 5 Provisions for the EARTH run In addition to performing the data specification for the disperse phase the GENTRA Menu will also make a number of provisions for GENTRA EARTH such as the allocation of auxiliary storage space or the set up of interphase sources The provisions made by the GENTRA Menu depend on the dimensionality of the problem the grid type the continuous phase variables that are being solved for and the particle type The setti
58. Group 17 Relaxation RELAX P1 LINRLX 2 000000 01 79 The GENTRA User Guide TR 211 GENTRA User Guide RELAX V1 FALSDT 3 333333E 03 RELAX W1 FALSDT 3 333333E 03 RELAX MOMZ LINRLX 7 000000 01 RELAX MOMY LINRLX 7 000000 01 C CK CC CC KKK KK KK KK KK KK KK KK KK CC CC Ck CK C CK C CK C CK CC KK KK KK KK Group 18 Limits VARMAX V1 1 000000 06 VARMIN V1 1 000000E 06 VARMAX W1 1 000000 06 VARMIN W1 1 000000E 06 C CK CC CC CC CC C CC CC CC CC CC CC CC CC CC Ck CK C CK C CK C CK C CC CC CC C Group 19 EARTH Calls To GROUND Station USEGRD T USEGRX ME 56001 GENTR T GENTRA GROUP 1 Particle physics Particle type 30 GPTYPE 30 Gravity components in GENTRA Cartesian system GGRAX 0 000000E 00 GGRAY 0 000000E 00 GGRAZ 9 800000E 00 Buoyancy forces GBUOYA F GSURPR Stochastic model of turbulence GSTOCH F Data for isothermal particles GDRAG GRND1 GENTRA GROUP 2 Boundary conditions for particles Inlet data file name GINFIL Q1 lt GENTRA INLET DATA gt ZP VP WP DI LDEN MDOT NUM 0 01 0 00 1 0 001 500 0 1 0 5 0 0
59. HO T KKEKKK ck ck cc Ck Ck CK CC Ck 0k CC CC Ck Ck Ck Ck c0 ck Ck c ko Sk Sk Sk ck kk ok ko kx ko ko Group 21 Print out of Variables KKEKKK ck Ck c CK C Ck CK C0 Ck Ck Ck C ck ck Ck ck ko Sk Sk Ck Ck kk ko ok ko kx ko ko Group 22 Monitor Print Out IXMON 1 IYMON 2 IZMON 20 NPRMON 100000 NPRMNT 1 TSTSWP 1 Group 23 Field Print Out amp Plot Control NPRINT 100000 2 2 5 NPLT 2 ISWPRF 1 ISWPRL 100000 PATCH DOMAIN CONTUR 1 1 1 12 1 30 1 1 LOT DOMAIN P1 0 000000 00 1 500000E 01 PATCH INNER PROEIL 1 1 2 2 1 30 1 1 LOT INNER 0 000000 00 0 000000 00 PATC LOT PATC LOT PLOT PLOT PATC LOT LOT LOT Gro H OUTER PROFII 1 1 12 1 30 1 1 OUTER Wl1 0 000000 00 0 000000 00 E H FRONT PROFIL 1 1 2 12 10 10 1 1 FRONT Pl1l 0 000000E 00 0 000000 00 FRONT V1 0 000000 00 0 000000 00 FRONT 0 000000 00 0 000000E 00 H BACK PROFIL 1 1 2 12 28 28 1 1 BACK Pl1l 0 000000 00 0 000000 00 BACK V1 0 000000 00 0 000000 00 BACK
60. LIBREF 237 G209 Particles in 2D curved duct BFC T CONJUGATE HEAT TRANSFER Group 3 Particles with heat transfer G301 Particle heating in pipe with constant gas temperature and particle velocity transient G302 Heat exchanging 1 d steady co a bt G303 Heat exchanging 1 d transient co a bt Group 4 Particles with solidification G401 Solidifying 1 transient m 3 0 G403 Solidifying 1 transient I l t G405 Isothermal solidification TRANSIENT 83 The GENTRA User Guide TR 211 GENTRA User Guide Group 5 Particles with mass transfer U502 U505 U506 U507 U508 Particle evaporating in pipe with constant gas temperature and particle velocity but changing vapour concentration particle temperature is also kept constant TRANSIENT Evaporating particles in spray dryer BFC Particles in 2D curved duct BFC T CONJUGAT HEAT TRANSFER Particles in 2D channel SOLVE H1 Isothermal evaporation constant prop s steady Group 6 Particle tracking with density calculation G722 Oblique impingement of box in water 84 The GENTRA User Guide Appendix G Listing of GENIUS TR 211 GENTRA User Guide
61. NS3 50 N DI D Di L5 07 Q 53 50 R2 0 00017741 ZZZ R3 0 01013139 1 50 CONS2 50 631141 HHH 1 2 50 THEN THI EXP EXP CONS3 TR 211 GENTRA User Guide 100 degC TDEGR 13023 8 TDEGR 100 degC lt Tcrit EGR TDEGR 951588 No super critical MAX1 1165 09 TDEGR CONS2 72 624453E included 0 0 5 CONS2 1 TD EGR END F Convert Psat from TDEGR TDEGR GT 50 folie Ow R1 15 182911 8310 453 TDEGR TD EGR2 TD EGR3 TD EGR1 50 DEGR1 5 GPROPS EXP ELSEIF FUNAME TD 68 0 15 94 76 0 lbf in2 to N m2 multiplying by 19 Heat capacity Cp of vapour 2 Q Y QC CY gprops paramt temp ratur heat capacity of vapour Cp is calculated under saturation condition T H he temperature sho EMQ AMAX1 PARAMT 273 15 100 0 GPROPS 1 2745 E 07 T 4 7457E O2 T EMO 3 8 7110 7TI ELSEIF FUNAME EQ 16 THEN uld be higher than 100 degree C EMO 5 1 2475E 04 TEMO 4 EMO 2 773 98 TEMQ 2 4505E 04 16 Cp of the continuous phase without vapour ns 0000020
62. NSTY FRATE TEMP NUMB In the table above POSTN is the parcel inlet position in the co ordinate system selected by the user for one or two dimensional cases no co ordinates are needed for the dimensions for which the number of cells are one VELOC is the parcel inlet velocity components in the co ordinate system selected by the user for one or two dimensional cases no components are needed for the dimensions in which the number of cells are one DIAM is the particle diameter DENSTY is the density of the particle LIQDEN is the density of the liquid phase in solidifying particles Units kg m3 FRATE is the mass flow rate of particles Units kg s TEMP is the particle temperature in K SOLDEN is for melting solidifying particles the solid phase density NUMB is an optional parameter indicating the number of parcels of the given characteristics to be released from that position When the stochastic turbulence model is active GENTRA will track every parcel separately When the stochastic turbulence model is inactive GENTRA will simply multiply the mass flow rate by the number of parcels and track a single parcel When the NUMB data item is missing one parcel is assumed Comments Those lines in the inlet table containing in any position an asterisk are treated as comments The table heading can be inserted in this way in the data file Blank lines are also ignored Line length The maximum length of an inlet
63. Q GSWEP1 THEN IF NOT LG 11 AND NOTGXM AND IZZ EQ 1 THEN WRITE BUFF 1 GENTRA resetting interphase sources to 0 CALL PRINT CHECK BUFF 1 LUPRO END F 88 The GENTRA User Guide 0000 Qa IF STORE ENDIF IF STORE ENDIF IF STORE MO MOMXZ AN CALL MOMZZ AN X MOMY MOMYZ AN CALL FN1 Y MOMZ YZ 2 MO 2 MO MX THEN MOMX 122 MXZ 0 0 THEN 122 2 0 0 MOMZ IZZ ENDIF CALL FN1 MO MZZ 0 0 IF STOR E HF H EATZ ANYZ AT THEN HEAT IZZ ENDIF H trj CALI ENDIF DIF IF CALL FN1 STORE MASSZ ANYZ MASS I ASSZ 1 0E FN1 HI n MASS GREST NE 0 ATZ 0 0 THEN THEN IF LOOPZ EQ 1 JREST ANYZ R CALL JRI ENDIF DIF NUE EST IZZ EST 0 0 ON AND LSTSWP AND STORE TR 211 GENTRA User Guide EST 3 START OF THE cal sources of momentum Its CALL is conditioned to G EL protected again NOT PSTLSW AND
64. Q1 file generated by the GENTRA 32 GENTRA 32 GENTRA Groups 1 to 4 GENTRA data 32 Provisions for the EARTH run 33 Transmission to 1 34 Exit and symmetry 34 Running Earth 35 35 The GENTRA i xke addu eo ceu daa 35 Results produced by 35 The GENTRA 38 noie eee sre 38 The structure of GENTRA EARTH 2 38 The FORTRAN subroutine GENIUS 2 1 2 2 2 39 The property function GPROPS ccccccessseseeeeeeeeeeeeeseeeeeeeeeeeeeeeeneness 43 Building private versions of 2 2 4 10 33 43 The GENTRA Equations ce ence 45 45 ii The
65. RO UPPARN UPPARO VAPSOL VCNDRG VCPARN VPPAHO REAL Old particle velocity in polar system UCNDRG__ REAL Internal variable for particle momentum calculation REAL Internal variable for particle momentum calculation WCPARO REAL Old particle velocity in Cartesian system WPGASN REAL Velocity of the continuous phase in polar system VCPARO REAL Old particle velocity in Cartesian system WPPAHN REAL New particle velocity in polar system VPPAHN REAL New particle velocity in polar system XCPARN XCPARO XPPARN XPPARO YCPARN YCPARO YPPARN YPPARO ZCPARN ZCPARO ZPPARN ZPPARO Printout variables Type X LUFAT LUHIS LUPRO LUTRA WCPARN REAL New particle velocity in Cartesian system WPPARO_ REAL Old particle velocity in polar system LUWAR Logical unit for GENTRA warning message TRCOLO Colour index of trajectory TRDASH line style index of trajectory 66 The GENTRA User Guide TR 211 GENTRA User Guide C 4 Auxiliary variables Name Type Meaning AXIXRY AXIXRZ AXIYRX AXIYRZ AXIZRX AXIZRY BNODAL CCHLIM CCLLIM CCNMAX CCNMIN CELMIN CENTRA CHARVL CNODAL DBGLEV DBGPAR DBGSWP DIHLIM DILLIM DISAX DISAY DISAZ DISBX DISBY DISBZ DNODAL ENODAL FACEVS FNODAL FULCYC FVISIT GBUOYA GCARTE GCPCON GCPLIQ GCPSOL GCPVAP GDRAG GDTMAX GDTMIN GDTRCT GFASWP GGRAX GGRAY GGRAZ GH1STC GHFILE GHLIQD GINFIL 67 The GENTRA User Guide TR 211 G
66. T M 1 12 30 Set overall domain extent xulast yvlast wlast name Set overall domain extent xulast yvlast wlast name XSI 1 000000 00 YSI 1 000000E 00 ZSI 1 000000E 00 RSET D CHAM Set objects x0 yO 20 2 name 0 000000 00 YPO 0 000000E 00 ZPO 3 333333 01 XSI 1 000000 00 YSI 8 333337E 02 ZSI 5 666666 01 RSET B CMPO 0 000000 00 YPO 0 000000E 00 ZPO 0 000000E 00 XSI 1 000000 00 YSI 1 000000E 00 ZSI 0 000000E 00 RSET B INLET 0 000000 00 YPO 0 000000 00 ZPO 1 000000E 00 XSI 1 000000 00 5 1 000000E 00 ZSI 0 000000E 00 RSET B OUTLET 0 000000 00 1 000000 00 ZPO 0 000000E 00 XSI 1 000000 00 5 0 000000 00 ZST 1 000000E 00 RSET B WFUN 0 000000 00 YPO 8 333337E 02 ZPO 3 333333 01 XSI 1 000000 00 YSI 0 000000E 00 ZSI 5 666666 01 RSET B VALVEWLL C CK CC CC CC CC C CC CC CC CC CIC CC CC CC CC CK CK C CK C CK C CK C CC CC CC C Group 6 Body Fitted coordinates READCO grid4 Ck ckCckck ck NONORT NCRT 1 KKK KKK KKK KKK KKK KKK KKK KKK KKK KKK KKK KKK KKK KKK KKK KKK KK KKK Group 7 Variables STOREd SOLVEd NAMEd ONEPHS Non default variable names 78 The GENTRA User Guide NAME 143 NAME 145 NAME 147 NAME 149 S
67. US is divided into groups some of which are further divided into sections that are visited at specific stages during the computation Users can insert their own coding in these groups in order to obtain additional results to compute auxiliary data and to influence the GENTRA computation Users are however advised that the modification of GENTRA variables particularly of those which affect the particle history should always be effected with great caution After a call to GENIUS the execution is directed to the appropriate group and section by the FORTRAN variables IGENGR GENIUS group and rGENSC GENIUS section and a network of computed GoTos Both IGENGR and IGENSC are set within GENTRA and the user should not modify their values The groups and sections of GENIUS are discussed now in this guide a list of the user accessible FORTRAN variables can be found in Appendix C and Appendix G contains the full listing of GENIUS 5 3 1 GENIUS Group 1 Preliminaries Group 1 is visited at the beginning of the first call to GENTRA in each EARTH run ie when ISTEP EQ FSTEP AND ISWEEP EQ GSWEP1 Group 1 is therefore a convenient place for the initialisation of local variables that are subsequently going to be used in GENIUS and since the group is visited after GENTRA has initialised its variables it is also the place to override the Q1 and default settin
68. WRITE BUFF 3 1160 50 15 15 15 7 8 CALL PRINT_CHECK BUFF 3 LUPRO ENDIF ENDIF IF LG 11 THEN IF NOTGXM CALL GRCLZZ 90 The GENTRA User Guide TR 211 GENTRA User Guide CALL CLOSZZ 44 IF LG 12 CALL CLOSZZ 43 ENDIF ENDIF ENDIF ENDIF 1150 FORMAT 2 RG 12 1PE9 2 RG 12 1PE9 2 1160 FORMAT RG 12 1PE9 2 RG 12 1PE9 2 END C ddp ia Dobis de ccn Mit E vut dari Eas eccentric ce den tet 8 e C Subroutine GENIUS C GENtra Interface for User Sequences e C Examples included GENEX1 Time step statistics GENEX2 Automatic generation of USE file for PHOTON C SUBROUTINE GENIUS IGENGR GENSC C Earth and GENTRA data imported via COMMONs in INCLUDE C files INCLUDE phoenics d_includ satear INCLUDE phoenics d_includ grdloc INCLUDE phoenics d_includ satgrd INCLUDE phoenics d_includ grdear INCLUDE phoenics d_includ grdbfc INCLUDE phoenics d_includ bfcear INCLUDE phoenics d_includ tracmn C C GROUP 1 Preliminaries G F IGENGR EQ 1 THEN C Section 1 Beginning of cur
69. a complete explanation Thermal conductivity of continuous phase This option must be selected A value of 0 0263 W m k is given as the default corresponding to air at STP If the user wishes to include his own temperature dependent function for the thermal conductivity of the continuous phase he should do the following 1 Replace the constant value in the menu with a GRND number GRND1 2 Modify function routine GPROPS in the file GENTRA FTN by adding coding in the relevant section For this case the coding should be added in the section commencing GROUND1 and in the subsection commencing 3 Thermal Conductivity of the continuous phase Coding relating the thermal conductivity GPROPS to the continuous phase temperature PARAMT should then be inserted 3 Before running EARTH the GENTRA file will have to be recompiled and the EARTH executable relinked The Nusselt number is defaulted to GRND1 This implies that the Nusselt number will be calculated from the correlation of equation 6 8 other correlations may be included in GPROPS following a procedure similar to that outlined above for the setting of the continuous phase thermal conductivity Alternatively the Nusselt number may immediately be specified as a constant during this menu session The specific heat capacity of the particle is defaulted to 4131 8 J kg k which is representative of liquid water Other constant values can be substituted for this or it can be re
70. a items in columns 68 onwards will be lost The inlet data table can be located anywhere in the Q1 file and is normally written using a system file editor after the menu session Note GENTRA can generally cope with inlets lying exactly on the boundaries of the domain or on the grid pole it is nevertheless a good practice to offset the inlet position by a small distance e g 1074 m In this worked example we will write the data table after finishing the menu session 2 7 1 3 Editing the File Containing the Input Data Table In the VR Environment the file containing the inlet data table can be opened for editing by clicking on File Open file for editing If the inlet data table is in Q1 select Q1 and then click Yes to save the current settings to Q1 After editing the inlet data table save the file and exit the editor Click Yes to reload the Q1 into VR Editor otherwise the new data will be lost To open any other file select Any file then open it from within the editor The editor used can be selected from Options Text file editor 2 7 2 Exits Particle exits in GENTRA are represented through PATCH commands Particle exit PATCHes must have names beginning with GX and be of an area type ie EAST WEST NORTH SOUTH HIGH LOW In the VR Environment all Inlet and Outlet objects act as GENTRA exits by default the PATCHes they create all have names starting with GX This behaviour can be a
71. above 2 7 Boundary conditions for particles The Boundary conditions button in the Main Menu panel figure 2 2 is used to specify the boundary conditions for the particles Boundary conditions fall into the following categories Inlets The injection position and the particle properties eg velocities diameter temperature etc at the inlet must be given Exits The boundary regions at which the particles can leave the domain must be specified Symmetry surfaces The location of the symmetry surfaces at which particles must be reflected must be supplied Wall obstacles The behaviour of the particle following the collision with a wall or obstacle is selected from a range of choices such as bouncing sticking or flash vaporisation Click on Boundary conditions to bring up the Boundary conditions panel Domain Settings GENTRA Boundary conditions Previous panel Inlet conditions Particle Exits Symmetry planes Wall obstacle treatment BOUNCE PARTICLE Restitution coefficient GWREST 1 000000 OK Threshold for obstacle porosity gporos Currently o 000000 PIL Command Figure 2 12 Boundary conditions for particles The options in the Boundary conditions panel shown in figure 2 12 are dealt with in subsequent subsections 19 The GENTRA User Guide 2 7 1 TR 211 GENTRA User Guide Inlet conditions The Inlet conditions option of the Boundary conditions panel produces the panel in figure
72. an time steps required for the particle to traverse the cell and for all particles The mass added to the continuous phase continuity equation represents fluid evaporated from the droplet surfaces A PHOENICS transport equation such as equation 6 1 is solved for the vapour mass fraction and sources must also be added to this equation to account for the vapour added from the particles The source in the vapour mass fraction equation is identical to that added to the continuity equation Momentum transfer The source of momentum Smom which appears in the continuous phase momentum equations is equal to the rate of change of particle momentum as each particle parcel traverses a cell x Smom 6 rnl pp Vp d59 3 Vp d5 3 6 43 where is the particle velocity integrated from the momentum equation without body forces Enthalpy transfer The source of enthalpy Sp which appears in the continuous phase enthalpy or temperature equation is Sh 6 hp dp Hp 9 1 3 6 44 55 The GENTRA User Guide TR 211 GENTRA User Guide where hp is the enthalpy of the particle relative to a value of zero at 0 0 K 6 6 Additional information 6 6 1 Stagnation criterion GENTRA will automatically detect whether a particle has fallen into a stagnation region and will stop the tracking of the particle if no heat or mass transfer effects are to be considered The stagnation criterion is based on the cont
73. ands that define your simulation Since the GENTRA Menu will translate your menu choices into fully commented Q1 settings you can also edit the Q1 file to effect small modifications once the menu has taken care of the bulk of the Q1 writing work This chapter explains how users can avail themselves of the GENTRA PIL for problem specification Section 3 2 below describes the group structure of the GENTRA settings in the Q1 file and subsequent sections deal with each GENTRA input data group 3 2 The Q1 file generated by the GENTRA menu The GENTRA menu will normally be called after some provisions have been made in the Q1 file for the specification of the continuous phase e g through another menu or by loading a PHOENICS Library case The GENTRA menu will add to the existing Q1 file a GENTRA section with the following parts a GENTRA declarations b Groups 1 to 4 GENTRA data c Group 5 GENTRA provisions for the EARTH run d Transmission of data to EARTH All these groups are described in the next subsections however you will only need to use groups 1 to 4 and occasionally group 5 The Qt file for the example of the previous chapter has been attached as Appendix E It can be referred to for exemplification 3 3 GENTRA declarations The first section inserted by the GENTRA Menu into the Q1 file is used for declaration and initialisation of the GENTRA PIL variables Users do not need to modify in any way this section The
74. as activated in the GENTRA menu but KE the continuous phase turbulence kinetic energy or EP its rate of dissipation are not stored in the Q1 file The stochastic turbulence model is automatically deactivated by GENTRA Remedy Activate the storage or solution of KE and or EP in the Q1 file through STORE SOLVE or SOLUTN or if using a menu system for problem set up choose a turbulence model that uses KE and EP Warning number 002 Stochastic turbulence model not available for stubborn particles Explanation The stochastic model for the dispersion of particles owing to turbulence was activated in the GENTRA menu but the particle type does not allow it The stochastic turbulence model is automatically deactivated by GENTRA Warning number 003 Particle removal is the only wall condition available for lazy and stubborn particles Explanation On hitting a wall or obstacle the lazy and stubborn particles are always removed from the computational domain Other wall effects are not available for these particles 70 The GENTRA User Guide TR 211 GENTRA User Guide Warning number 004 GENTRA first sweep less than FSWEEP Explanation The user has specified a GENTRA first sweep that is less than FSWEEP the EARTH first sweep The GENTRA first sweep is reset automatically to FSWEEP Warning number 005 Particle ip initially in wrong position Tracking for the particle skipped Explanation The initial position of a pa
75. by GENTRA are RG RG 71 to RG 100 IG IG 9 to IG 20 LG LG 10 and LG 19 to LG 20 CG CG 6 to CG 10 3 7 Exit and symmetry patches Exit and symmetry patches created through Inlet Outlet and GENTRA SYMMETRY objects see Section 2 7 are written to the EARDAT file directly and do not appear in the Q1 file Inlets and outlets which do not act as GENTRA outlets have the additional line OBJ GENTRA EXIT 1 000000E 00 as part of their definition The absence of such a line is a signal that the inlet or outlet does act as a GENTRA exit GENTRA_SYMMETRY objects are written to the Q1 as gt OBJ NAME name gt OBJ POSITION Xorigin Yorigin Zorigin gt OBJ SIZE Xsize Ysize Zsize gt OBJ CLIPART DEFAULT gt OBJ TYPE GENTRA_SYMMETRY 34 The GENTRA User Guide TR 211 GENTRA User Guide 4 Running GENTRA Earth 4 1 Introduction Chapters 2 and 3 explained how to prepare input data for GENTRA using the PHOENICS SATELLITE This chapter explains how to run GENTRA EARTH and where the results of the run can be found 4 2 The GENTRA run GENTRA is linked in to the standard EARTH executable To run EARTH from the VR Environment click on Run Solver then Local solver Earth PHOENICS VR Editor File Edit View Run Options Compile Build Demos Help Dicam Commander g Pre processor Local Solver Earth Remote Solver Earth
76. can either be removed from the domain or bounced with a user supplied restitution coefficient e Heat exchanging particles Transfer of momentum and enthalpy between the continuous and disperse phases is accounted for when heat exchanging particles are employed The particles are modelled by Lagrangian equations for the particle position velocity and temperature Melting solidifying particles Melting solidifying particles are modelled a similar way to heat exchanging particles However the Lagrangian equation for the particle temperature includes the effects of solid liquid and liquid solid phase change and the particle diameter is determined as a function of the proportion of the solid and liquid phases present e Vaporising droplets Vaporising droplets are modelled by Lagrangian equations for the particle position velocity temperature and mass Exchange of momentum enthalpy and mass between the disperse and continuous phases is included The choice of a particle type should normally be your first action when using the GENTRA Menu as some of the menu options e g those concerning physical data or particle obstacle interaction will depend on the type of particle 2 6 Physics of current particle type The settings button on the Particle type panel enables the user to specify values for the particle physics such as drag law Nusselt numbers specific heat buoyancy effects turbulent dispersion The data items to be suppli
77. ce model is selected the particle trajectories will be calculated from the sum of the mean continuous phase velocity and an instantaneous turbulent velocity fluctuation determined from the local turbulence conditions b Data for stubborn particles No additional data is required for this particle type 13 The GENTRA User Guide TR 211 GENTRA User Guide c Data for isothermal particles Domain Settings 31 x Previous panel GENTRA Data for isothermal particles Drag coefficient GDRAG Currently GRHD1 Gravity buoyancy Stochastic turbulence model GSTOCH Currently HOT ACTIVE PIL Command Figure 2 7 Data for isothermal particles The drag coefficient which is responsible for the exchange of momentum between the disperse and the continuous phase can be specified in one of two ways e lfaconstant is used the drag coefficient will be taken as equal to that constant Special flags can be used to specify laws The built in laws and associated flags are as follows Flag Law GRND 1 10120 Solid spheres See Chapter 6 of this Guide for mathematical expressions You can introduce your own law in Section 1 of GPROPS see Chapter 5 for details Recompilation and re linking of EARTH is needed after the modification of GPROPS T The built in law will suffice for the worked example However you can enter other values then enter GRND1 again for the sake of practice Then re
78. cell as At oe x 6 47 k cell where k represents a parcel of particles Vk is the volume of each particle nk is the number flow rate for the parcel At is the residence time of the parcel in the cell and is the cell volume For unsteady flows STEADY F when STORE PVFR appears in the Q1 file see Section 2 9 3 a particle volume fraction is computed for each cell as 6 48 57 The GENTRA User Guide TR 211 GENTRA User Guide 6 6 5 Particle mass concentration When STORE PMCO appears in the Q1 file see Section 2 9 4 a particle mass concentration Cp is computed for each cell For steady flows the particle mass concentration is computed for each cell as N p Vm C y k l cell 6 49 where p is the density of each particle For unsteady flows it is computed for each cell as 6 50 N s pae k l cell 6 6 6 Mixture density When STORE RHMX appears in the Q1 file see Section 2 9 5 a mixture density is computed for each cell as P U C 6 51 where is the density of the continuous phase 6 6 7 Particle mass fraction When STORE PMFR appears in the Q1 file see Section 2 9 6 a particle mass fraction Yp is computed for each cell as Meme Ee 6 52 p m 58 The GENTRA User Guide TR 211 GENTRA User Guide Appendix A Known Limitations of GENTRA This entry provides a summary of those limitations of GENTRA known to the GENTRA Deve
79. component of the force exists then the user should add the following coding in this section GVCSCX GVCSCX GMX As another example the following coding replicates the built in particle momentum equation REYNOL RENLF DIPARO RELVEC GSENUL CDRG GPROPS 1 REYNOL GDRAG GVCSAA 3 0 GSENUL DENGAS CDRG REYNOL 4 0 ROPARN DIPARO 2 GVCSBB GVCSAA where GPROPS and RENLF are GENTRA function subroutines and all the FORTRAN variables appearing on the right hand side are in local common blocks see the common block file TRACMN The values of GVCSCX GVCSCY and GVCSCZ will already have been set in GENTRA Section 2 Particle energy equation This section is called before the energy equation is solved but after the coefficients and sources GHCSAA GHCSBB GHCSCC have been calculated The user can change the terms in the energy equation in the same way as for the momentum equation Section 3 Particle mass equation This section is called before the mass equation is solved but after the coefficient and sources GMCSAA GMCSCC have been calculated Beware that instead of solving particle mass or particle diameter the square of the particle diameter is chosen as the dependent variable Section 4 Particle solidification In this section the user can change the built in model for particle solidification which is a function of particle temperature Section 5 User s own Lagrangian equations The user can write his own particle
80. ction 6 3 2 for details e Force on particle due to pressure gradient This option activates deactivates the pressure gradient term in the particle momentum equation see Section 6 3 2 for details If P1 includes the hydrostatic pressure then the user selects a pressure gradient term to active and buoyancy term to not active to include all the fluid forces on the particle or b pressure gradient term to not active and the buoyancy term to active to include only buoyancy If P1 excludes the hydrostatic pressure reduced pressure formulation then the user should select a pressure gradient term to active and buoyancy term to active to include all fluid forces on the particle b pressure gradient term to not active and buoyancy term to active to include only buoyancy 15 The GENTRA User Guide d TR 211 GENTRA User Guide Data for heat exchanging particles Domain Settings E n GENTRA Data for heat exchanging particle Previous panel Drag coefficient GDRAG GRND1 Thermal conductivity of continous phase GKONC 0 026300 Nusselt number GHUSS GRND1 Cp of particle GCPLIQ 4131 800 Cp of continuous phase GCPCON 1007 000 Gravity buoyancy Stochastic turbulence model gactiv Currently HOT ACTIVE PIL Command Figure 2 9 Data for heat exchanging particles The selection of drag coefficient is identical to that for the case of isothermal particles see subsection c above for
81. e ee tes Le 73 0 4 Internal 76 Appendix E Listing of the Q1 File for the 77 Appendix F Contents of the GENTRA Input Library 83 Appendix G Listing of GENIUS 22 2 nnn 85 Appendix GENTRA 101 Appendix 2 ieee eat ag 103 1 1 Quoted In this guide vs ssh eee 103 1 2 Relevant CHAM Technical Reports 103 Appendix J Nomenclature eeeeeeeeeeeeeeeee eene eene nennen nnn nnne annnm 104 Appendix K GENTRA Utilities ceeeueeeeeeeeeen nnne nnn 106 1 Plotting Trajectories iere enne trn enn tian eno iuuenis 106 Kez Saving s d Case nee Deui 107 iii The GENTRA User Guide TR 211 GENTRA User Guide 1 Introduction 1 1 What GENTRA is and does GENTRA is a software add on for the PHOENICS suite of CFD programs which provides particle tracking facilities The name GENTRA stands for GENeral TRAcker GENTRA can therefore simulate the motion of particles the particulate or disperse phase through a fluid the continuous phase GENTRA takes into account the effect of the fluid velocity temperature turbulence etc
82. e Explanation One of the symmetry or exit patches declared by the user has a patch type such as CELL VOLUME LWALL etc which is not of the area type patchname is the name of the patch causing the error Remedy Change in the Q1 file the patch type to one of the allowed types listed above The help facility in the GENTRA menu system provides advice on patch types The SATELLITE must be re run after changing the Q1 file but the GENTRA menu does not need to be loaded again Error number 311 Variable out of range Variable var Value value Valid range range Explanation Variable var was supplied a value which is not within the permissible range Error number 312 GENTRA cannot be used for PARABolic flows Explanation 75 The GENTRA User Guide TR 211 GENTRA User Guide GENTRA cannot be used in conjuction with the parabolic option of PHOENICS activated by PARAB T Remedy Parabolic flows can also be solved as elliptic by supplying outlet boundary conditions and setting PARAB F D 4 Internal errors Errors with numbers greater than 600 are internal errors Internal errors should be reported to CHAM via the User Support Team Please e mail the Q1 causing the error to CHAM and report as many details as you can further details might be requested by CHAM upon notification of the error e mail support cham co uk 76 The GENTRA User Guide TR 211 GENTRA User Guide
83. e default value of 0 0263 is for air at STP Nusselt number see Subsection d for explanation Cp of liquid phase of the melting solidifying particle The value of 4131 8 is representative of water Cp of solid phase of the melting solidifying particle Cp of continuous phase Latent heat of solidification The default value of 3 335E 05 is for the formation of water ice If the specific heat capacities of the liquid and solid phases were not identical and if the change of phase was not isothermal the latent heat of solidification would be temperature dependent and a function would be required for it in GPROPS Further explanation of this is provided in Section 6 3 4 Index for solid fraction formula equation 6 15 For the case of isothermal phase change this variable is not employed Solidus temperature of particle The maximum temperature at which the particle is completely in the solid phase The default value is for water Liquidus temperature of particle The minimum temperature at which the particle is completely in the liquid phase The default value is for water Gravity buoyancy pressure forces See Subsection c above for this option Stochastic turbulence model See Subsection a above for details on this option 17 The GENTRA User Guide TR 211 GENTRA User Guide The constant values which appear in this menu can be replaced with functions set in function routine GPROPS according to the method described i
84. e temperature ELSEIF IGENSC EQ 12 THEN PRVLIN 350 0 C Cain Section 12 Density of the solid ELSEIF IGENSC EQ 13 THEN ENDIF C 94 The GENTRA User Guide TR 211 GENTRA User Guide END ENDIF END C FUNCTION GPROPS FUNAME PARAMT DEFVAL e Functions to calculate liquid and gas properties for GENTRA Only one parameter is permited for each function others C are passed through TRACMN FUNAME character string name of the function PARAMT real parameter of the function e DEFVAL real default value C C INCLUDE phoenics d includ satear INCLUDE phoenics d includ tracmn INCLUDE phoenics d includ grdloc INCLUDE phoenics d includ satgrd NTEGER FUNAME LOGICAL FINDGR GRN CHARACTER 80 BUFF if dbglev and dbgrnd then call writli findx funame call writ2r paramt paramt defval defval endif Default value or Ql set flag 0000 a GPROPS DEFVAL GROUND 1 WATER AND AIR IF GRNDNO 1 DEFVAL THEN IF FUNAME EQ 1 THEN Drag coefficient 0000020 gprops drag coefficient defval ql set flag paramt particle Reynolds number TEEF Law for spherical particles GPROPS 24 0 PARAMT 1 0 0 15 PARAMT 0 687 t 0 42 1 4 25E 4 PARAMT 1 16 ELSEIF FUNAME EQ 2 THEN
85. ecial sets of files can be generated by GENTRA one for the particle trajectories and another for particle histories see Section 2 9 for details e The trajectory file is provided for the plotting of particle trajectories with the PHOTON post processor The file is read as a PHOTON geometry file by using the command GEOMETRY READ A trajectory file is produced for each particle EARTH also creates a VR Viewer macro file PHOTON USE file called GENUSE which draws all the saved trajectories A plot of the particle trajectories for the worked example of Chapter 2 created by using the GENUSE macro can be seen in Figure 4 2 36 The GENTRA User Guide TR 211 GENTRA User Guide PHOENICS VR Viewer EC Inl x File Edit View Run Options Compile Build Demos Help 5 F3 Faro Probe value 1 095E 04 FLOW THROUGH A BALL VALVE 534 Figure 4 2 Particle tracks from the worked example e The history file contains a record in tabular format of the evolution of the particle properties position velocity temperature size etc with time This can be used by the PHOENICS post processor Autoplot for the plotting of graphs of the x versus y kind It can also of course be used for the user s own analysis programs An additional global history file may also be created This file contains data for several particles which can subsequently be processed to produce individual history and
86. ect of modelling features GENTRA can track particles in all the co ordinate systems supported by PHOENICS i e Cartesian cylindrical polar and general curvilinear BFC e GENTRA can solve both steady and transient problems GENTRA can model particles of six kinds a Tracers or lazy particles which simply follow the continuous phase flow field b Beams or stubborn particles which have a constant velocity regardless of the continuous phase flow field c Particles in isothermal flow d Particles experiencing heat exchange with the continuous phase e Melting solidifying particles f Vaporising droplets ndun will automatically detect internal walls and obstacles and provides options Or a b Particle bouncing with a user specified restitution coefficient Particle adhesion to the wall c Withdrawal of the particle Flash vaporisation of the particle if the particle is droplet c In respect of post processing e GENTRA can generate input files for the PHOENICS post processors VR Viewer PHOTON and Autoplot e For VR Viewer and PHOTON it generates trajectory files which record the trajectory of the particle as it moves through the domain e For Autoplot it generates history files which record the evolution of the particle properties with time 1 3 Limitations of GENTRA As well as capabilities GENTRA has also l
87. ed are dependent on the particle type selected in the previous menu panel The user is therefore advised to select the correct particle type before visiting this data section 11 The GENTRA User Guide TR 211 GENTRA User Guide The following subsections describe the data panels for each of the available particle types 12 The GENTRA User Guide TR 211 GENTRA User Guide a Data for lazy particles Domain Settings 18 p GENTRA Data for lazy particle Previous panel Stochastic turbulence model GACTIV Currently NOT ACTIVE PIL Command Figure 2 6 Data for lazy particles The only data required for lazy particles concerns the use of the stochastic turbulence model for particle dispersion GENTRA has a built in model that simulates the effect of the turbulent fluctuations of the continuous phase velocity on the dispersion of particles The selection of the option Stochastic turbulence model in the Particle physics menu figure 2 6 will alternately activate deactivate this feature Try this now by clicking not active the stochastic turbulence model will be activated Click active and it will be deactivated again Then return to the GENTRA main menu panel by choosing Previous panel Note that for the stochastic model to be available the k e model of turbulence must be used GENTRA EARTH will automatically deactivate it if KE and or EP are not SOLVEd for or at least STOREd When the stochastic turbulen
88. eference manual for GENTRA users 3 The GENTRA User Guide TR 211 GENTRA User Guide GENTRA as indeed PHOENICS has been created to cater for the needs of users with several degrees of knowledge or experience New and occasional users who want to access the system will find the GENTRA Input Menu to constitute a fast lane for it can be used to set up problems with very little knowledge of PHOENICS or CFD Chapter 2 of this document The GENTRA Input Menu has been provided as a guide Its reading is however by no means compulsory for most of the information it conveys is also available as on line help to menu users Expert users or users with unusual needs will want to know exactly what GENTRA does and how it does it and may wish to ascertain whether the system can be expanded and how For this second class of users a reference element has been included in this guide notably Chapters 3 The GENTRA PIL 5 The GENTRA FORTRAN and 6 The GENTRA Equations A basic knowledge of PHOENICS and its structure is assumed in this Guide 1 5 2 How this Guide is organised After this introductory chapter the reader will find the following chapters and appendices Chapter 2 The GENTRA Input Menu which is intended mainly for beginners describes how to use the GENTRA menu to set up particle tracking problems Chapter 3 The GENTRA PIL explains how more experienced users can avail themselves of a sub set of PIL variables that circ
89. form 3 0 9 V V Sot Sie 6 1 where is the continuous phase property modelled Pc is the continuous phase density Uc is the continuous phase velocity is an exchange coefficient for So are the sources sinks of and SoG the interphase sources computed by GENTRA and accounting for the transfer of c between the phases Equations such as equation 6 1 are set up by PHOENICS following the instructions supplied by the user through the PHOENICS Input Language or a PHOENICS menu The variables for which GENTRA will expect PHOENICS to solve equations like equation 6 1 vary from problem to problem as follows a For all particle types except for stubborn particles GENTRA requires the velocity component in each of the co ordinate directions considered U1 V1 W1 b For particles with heat transfer melting solidifying particles and vaporising droplets an equation for enthalpy H1 or temperature TEM1 is also required c For vaporising droplets the mass transfer term 5 in equation 6 1 is inserted into the equation for P1 which in PHOENICS is the continuity pressure correction equation and a transport equation must also be set up for VAPO the mass fraction of droplet vapour in the continuous phase d When the stochastic turbulence model is used the equations for KE turbulence kinetic energy and EP its rate of dissipation must also be solved
90. gs for the GENTRA variables Users can for instance change the logical units for the output files see variables LUPRO LUWAR LUERR LUTRA LUHIS in Appendix C 39 The GENTRA User Guide TR 211 GENTRA User Guide 5 3 2 GENIUS Group 2 Start of new track This group is visited at the beginning of the tracking of each particle once e the particle data has been read from the inlet data table and stored in the F array e all the variables for the track such as the particle number IPARTI the absolute time TIME the cell residence time CTIME have been initialised and e the trajectory and history files have been opened if the user has requested such output and the current sweep is the last one GENTRA calls this group before it locates using the particle inlet co ordinates the indices of the cell where the particle is initially located Users can therefore override in this group the settings in the inlet data table for the particle inlet position and properties This is particularly useful when the particles obey a size velocity or density distribution In this case dummy properties can be used in the inlet data and these can be subsequently overwritten in GENIUS To do this the particle variables to be set in GENIUS are the ones ending in N in the list provided in Section C 2 The values will be subsequently transferred to the corresponding 0 variables by GENTRA You do not need to suppl
91. hases of the particle as functions of the particle temperature The latent heat of solidification of the particle is defined as the difference in total enthalpy of the solid and liquid phases at a given temperature T T Ls C dT hyo 6 14 where hso isthe enthalpy of the solid phase at the reference temperature of 0 0 K and is the enthalpy of the liquid phase at the same reference temperature In the case of the specific heat capacities of the two phases being equal the latent heat of solidification is independent of temperature and equal to hig Ngo The solid fraction of the particle is determined from the following equation TL T m fs 17275 6 15 where Ts isthe solidus temperature of the particle TL isthe liquidus temperature of the particle and m isthe solidification index The particle heat transfer coefficient a is determined from a kc Nu dp 6 16 where is the thermal conductivity of the continuous phase The particle enthalpy equation is not used in the simulation of lazy stubborn or isothermal particles For the other particle types it is employed in the following reduced forms Heat exchanging particles dT mp Cp ge o Tg Tp 6 17 in which the terms representing solidification melting and evaporation are absent Melting solidifying particles dT dfs Mp 9 0 Tg Tp 6 18 in which the term representing evaporation is not present
92. he Cartesian components must be 1 Remedy Set NCRT 1 in the Q1 file then re run the SATELLITE and EARTH Error number 305 GENIUS called but property not set Property prop Explanation A GRNDn flag was used for the particle property prop indicating that its value was to be computed in the FORTRAN subroutine GENIUS However no value for the property was supplied there Remedy Insert the appropriate coding in GENIUS and then re compile and re link 73 The GENTRA User Guide TR 211 GENTRA User Guide Error number 306 Inlet data from Q1 but no GENTRA INLET DATA mark Explanation The user has specified that the Q1 file is the file where the inlet data table is to be found but GENTRA could not find the lt GENTRA INLET DATA gt mark Remedy If there is no lt GENTRA INLET DATA gt mark at the beginning of your data insert it If there is check that the line starts from the third column of the Q1 file the mark is separated from other text in the line by blank spaces there is not an asterisk in the same line Error number 307 F Array too small for particle data Current size size Increase Explanation GENTRA stores the particle inlet data in the F array the central storage array of EARTH The message is produced when there is not enough F array space to store further particles size is the current F array size Remedy You can increase the F array dimension by changing the
93. he particle loading will not be a high one in the worked example the default value will suffice Maximum time step This option allows the user to specify a maximum Lagrangian time step which will not be exceeded by GENTRA Note however that this time step may be reduced by GENTRA according to particle position and flow conditions Time steps cell This option sets the approximate number of integration steps for each particle within each cell A value of 5 is recommended Note that this number can be increased and occasionally reduced by GENTRA according to flow conditions See Section 6 5 1 Max number of time steps This option allows the user to specify a maximum number of Lagrangian time steps If this limit is reached during the tracking of a particle the particle is abandoned a timeout message is issued and GENTRA moves on to the next particle This device can for instance avoid large computing times arising from very small time steps The step number n can be positive negative or zero e n gt 0 abandons the tracking after n time steps e n 0 deactivates this timeout device e n 0 indicates that the time step limit is to be applied in each cell ie the timeout counter is reset when the particle enters a new cell Enter 100 for the worked example Flight timeout This option allows the user to specify a time limit for the tracking If this limit is reached during the tracking of a particle the particle is aband
94. hed a wall or obstacle Note that the visit to GENIUS takes place after the velocity components have been changed after bouncing if the particle is to be bounced GENSC 3 means that the particle has been reflected at an axis surface of symmetry 40 The GENTRA User Guide GENSC 4 TR 211 GENTRA User Guide means that the particle is in a new cell note that the particle might in this case be inside the new cell and not just on the boundary 5 3 5 GENIUS Group 5 End of current Lagrangian time step Group 5 of Gi EN IUS is called at the end of the current Lagrangian time step after e the cell residence time CTIME and the absolute time TIME have been increased by GDT the current time step size e the several end of tracking criteria such as timeouts have been checked e the cell residence time CTIME has been reset if the particle is in a new cell and transferred to the full field store in EARTH if the current particle is GRESTI Users can in group 5 of GENIUS kill the tracking of the particle by setting the logical variable KILPAR to TRUI GENTRA will start tracking the next one E The tracking of the particle will be then abandoned and 5 3 6 GENIUS Group 6 End of current track Group 6 of Gi ENIUS is visited before finishing the track for the current particle and moving on to
95. hich for this reason is not discussed in this Guide GENIUS GENTRA Interface for User Sequences is the GENTRA open source subroutine where users can insert FORTRAN coding to supplement or replace the built in features GENIUS is called by GENTRA at well defined stages during the solution of the particulate phase GENIUS can therefore be regarded as the counterpart for GENTRA of the EARTH GROUND e GPROPS is the particle property function routine in which properties of the particulate phase may be set 38 The GENTRA User Guide TR 211 GENTRA User Guide Regarding the filing arrangements all of the open source routines are provided within the file gentra htm This can be edited from the VR Environment by clicking on File Open file for Editing and selecting gentra Edit View Run Options Compile Buid Start New case 8 Open Existing case Load from Libraries Reload Working files Open file for Editing Save Working files Save As a Save Window As ave Window As Config Cham ini main ground satiit photon gentra Add File Exit Figure 5 2 Opening GENTRA HTM for Editing A reference copy of this file is kept in the phoenics d_earth d_opt gentra directory Users can copy this to their private directory for modification 5 3 The FORTRAN subroutine GENIUS GENIUS is similar in concept and format to the EARTH subroutine GROUND GENI
96. hod employed for the integration of the particle mass equation which is cast into the form of an equation for the rate of change of particle surface area 2 thus 4 2 4 k adp 4 v ac Pp Coy Nu In 1 6 34 53 The GENTRA User Guide TR 211 GENTRA User Guide This is integrable using equation 6 31 in which the constant A is equal to the right hand side of equation 6 34 Ak Nu In 1 6 35 The rate of change of particle mass is then deduced from the change in particle diameter The particle enthalpy equation The particle enthalpy equation its most general form is given by equation 6 12 thus dT dr d Ep 248 mp mp Co G 0 Tg Tp Before integrating this the solidification melting term is expressed a more useful form by noting the relation between the solid fraction fs and the particle temperature tp equation 6 15 T ML This can be differentiated with respect to the particle temperature yielding d TL Tp 1 Ai gg A I 6 36 m dTp TL Tg and the original term representing the rate of change of solid fraction with time can be expressed as dis _ 1 dt TL Ts dt This may be substituted into the general particle enthalpy equation which may be written in the form of the general particle equation equation 6 29 dTp Hig dmp dt dt mp Op lm Q mp Cp Lm Q psu where TL Tp Ga Tp 6
97. ile which plots them will also be written K 2 Saving as a case The global history file ghis will be automatically saved as case his by clicking on File Save as a case The genuse file will be saved as case gen The individual trajectory and history files will not be saved automatically They can always be recovered from ghis by running the track unpacker as described above 107 The GENTRA User Guide
98. ill be transferred to the continuous phase This option is available only for VAPORISING DROPLETS 2 7 5 Threshold for obstacle porosity This option of the Boundary conditions panel figure 2 12 allows the user to set the level of porosity that will be considered by GENTRA to constitute an obstacle for the particles For instance a value of 0 75 will indicate that cells and cell faces with porosities between 0 0 and 0 75 will be taken as obstacles for the particulate phase Only values between 0 and 0 999 are accepted 24 The GENTRA User Guide TR 211 GENTRA User Guide 2 8 Numerical controls The option Numerical controls of the main menu figure 2 2 allows the user to control the solution procedure for the particulate phase Users can for instance Delay the first call to GENTRA until the continuous phase flow field has settled Specify a frequency for calls to GENTRA Set timeout limits for the particle flights Apply relaxation to the interphase sources Domain Settings EC 21 GENTRA Numerical controls Previous panel GENTRA call controls 1st GENTRA sweep GSWEP1 1 Sweep frequency for GENTRA GSWEPF 1 Time time step control Maximum time step GDTMAX 1 000000 Time steps cell GLAGTS 5 Max number of time steps GSTEMX 0 Flight timeout GTIMMX 0 000000 Relaxation Relaxation factor for sources GLHRLX Currently 1 000000 Time step size multiplier GRTFRC Currently 1 000000 PIL Command
99. imitations Appendix A of this guide provides a list of the main limitations known to the GENTRA Development Team at CHAM The contents of the list changes as known limitations are removed and new ones found An updated list of the limitations affecting your version of GENTRA if different from the one described in this manual is available through the GENTRA Input Menu Help and information panel See Section 2 4 of this Guide for details 2 The GENTRA User Guide TR 211 GENTRA User Guide 1 4 How GENTRA fits in Section 1 1 above classified GENTRA as a PHOENICS add on The present section describes in more detail how GENTRA is related to the rest of PHOENICS GENTRA has a pre processing and a processing part which are dealt with in the following sub sections 1 4 1 Pre processing The pre processing part involves the preparation of the GENTRA input which consists of particle data solution control data and output control data It can be accomplished in several alternative ways a By using the GENTRA Input Menu b By using a set of special PIL commands the GENTRA PIL c By loading a case from the GENTRA Input Library The pre processing side of GENTRA uses the general PHOENICS VR environment For the benefit of experienced PHOENICS users it will be pointed out here that all the GENTRA information is sent from the Q1 file to EARTH through the transfer arrays RG IG LG and CG 1 4 2 Processing The processing part of
100. inuous phase velocity Uc the particle velocity Upl and a characteristic velocity Uchar The tracking of the particle is abandoned if lUc Upl US r 6 45 where r is a constant The characteristic velocity Uchar is computed for each time step as the maximum of Up and the existing value of Uchar The FORTRAN variables representing the different elements of equation 6 45 are as follows Uc is GVFLOW it can be inspected by the user in GENIUS but it is set only by GENTRA Up is GVPART it can be inspected by the user in GENIUS but it is set only by GENTRA Uchar iS CHARVL it can be set by the user in GENIUS eg in Group 3 but the maximum value referred to above will nevertheless be taken by GENTRA and Uchar will be accordingly changed and r is STARAT it has a default value of 0 01 but it can be set by the user at the beginning of the GENTRA run GENIUS Group 1 of the track GENIUS Group 2 or of the time step GENIUS Group 3 6 6 2 Particle bouncing When a particle tries to cross into a wall or obstacle during a time step GENTRA will reduce the time step so that the particle is placed on the wall or obstacle surface If the user has specified that the particle is to be bounced with a given restitution coefficient the particle velocity is modified as follows see figure 6 1 a The velocity component parallel to the wall after the bounce equals
101. is of symmetry e In wedge like 2D BFC domains in which one of the domain sides collapses to a line the edge of the wedge is treated as a symmetry axis In all other cases axes surfaces of symmetry must be declared by the user so that GENTRA can act appropriately when a particle hits the axis surface Symmetry surfaces in GENTRA are represented through PATCH commands whose PATCH name starts with GS Each symmetry PATCH has also an associated PATCH type This indicates on which face of the cells covered by the PATCH the symmetry surface is The PATCH type can be EAST WEST NORTH SOUTH HIGH or LOW In the VR Environment GENTRA symmetry surfaces are created by making a new object with type GENTRA SYMMETRY This object type is only available when GENTRA is active The PATCH created by such an object will have a name starting with GS and will be of the correct type The grid in the worked example is of the wedge like kind the axis will therefore be automatically detected by GENTRA 2 7 4 Wall obstacle treatment The option Wall obstacle treatment in the Boundary conditions panel figure 2 12 specifies how the particle interacts with walls and obstacles e g bouncing sticking removal 23 The GENTRA User Guide TR 211 GENTRA User Guide See the GENTRA Glossary for a definition of wall obstacle The options available depend on the type of particle the user is therefore advised to set the particle type before visiti
102. ll depend on the dimensionality of the problem For this reason you are advised to enter the GENTRA menu after the continuous phase settings have been effected 2 2 4 Obtaining help All the menu options have associated help entries To obtain help on an option click the question mark at the top right corner of the dialog box then click on the item in question 2 3 The GENTRA Main Menu panel If you are following the worked example provided in this chapter enter the PHOENICS VR environment Click on the PHOENICS icon on the desktop or click on Start Programs PHOENICS PHOENICS Load the PHOENICS Library Case B534 by clicking on File Load from Libraries entering B534 and clicking OK This case simulates the flow of a liquid water through a ball valve and will be used as the basis of the worked example Particles e g solids in suspension will be included in the flow simulation by means of the GENTRA Input Menu After loading the case you can inspect the settings by double clicking on the various objects to bring up their Attribute dialog boxes and check the domain settings by clicking on Menu on the hand set Once you are ready to move on to GENTRA click on Menu on the hand set then on Models turn GENTRA ON and click on Settings After loading the GENTRA menu as detailed in Section 2 2 the first menu panel to appear on the screen is the GENTRA Main Menu Panel shown in figure 2 2 The optio
103. lopment Team at CHAM The list is not intended to be exhaustive but the main limitations are nevertheless listed and where possible alternatives are suggested Most of these limitations will be removed in future versions of the software BFC GRIDS Only right handed XYZ and IJK systems are allowed Two dimensional BFC grids are treated internally as having a uniform thickness in the third direction equal to XULAST YVLAST or ZWLAST as appropriate Note that this is an INTERNAL arrangement that does not affect the user other than that trajectories will only appear correct if viewed head on with no perspective CHEMKIN GENTRA cannot be used in combination with the PHOENICS CHEMKIN interface without user intervention The reason is that GENTRA operates in SI units whereas CHEMKIN employs cgs units CYCLIC BOUNDARY CONDITIONS In BFC cases only cyclic boundaries which are coincident in physical space may be used FIXVAL OBSTACLES GENTRA will not recognise obstacles that are represented by FIXVALing the velocity components to zero as is the case at the surface of solids in conjugate heat transfer problems However in such problems a property index field PRPS is stored the value of which denotes the material or fluid in each cell PRPS values greater than a certain number 99 by default represent solid materials and GENTRA tests the PRPS field if it is stored to determine the presence of solid obstructions This method cannot be
104. ltered by the Acts as GENTRA exit buttons at the foot of the Inlet and Outlet object attribute dialogs Note that these buttons only appear once GENTRA is active The buttons can be seen in Figure 2 14 22 The GENTRA User Guide TR 211 GENTRA User Guide Object Attributes E 32 x Object Attributes Em 21 Inlet density is Domain fluid External pressure 0 000000 Pa Method Velocities Relative to 0 000 00 Pa X Direction 0 000000 m s Coefficient 1000 000 Y Direction 0 000000 m s Z Direction 14 00000 m s External values used ONLY when inflow Velocity X User set 0 000000 m s Velocity Y User set 0 000000 m s Acts as GEHTRA exit Velocity Z User set 0 000000 m s Acts as GENTRA exit Yes Figure 2 14 Inlet and Outlet attribute dialogs To create an exit where only particles can leave the domain set the coefficient for the pressure to zero in the Outlet attributes dialog This will prevent the continuous phase from passing through 2 7 8 Symmetry surfaces The treatment for particles at an axis surface of symmetry is always reflection i e bouncing with a restitution coefficient of 1 regardless of the wall treatment selected for the problem GENTRA will automatically detect symmetry axes in the following two circumstances e n 2D cylindrical polar cases and 3D cylindrical polar cases in which the domain covers less than 27 radians in the circumferential direction the grid pole is treated as an ax
105. main Settings 2 x Geometry Models Properties Initialisation Help Top menu Sources Numerics GROUND Output Debug Equation formulation Elliptic Staggered The simulation is ONE PHASE Lagrangian Particle Tracker GENTRA OFF Solution for velocities and pressure Free surface models OFF Energy Equation OFF Turbulence models LVEL settings Radiation models OFF Combustion models OFF Solution control Extra variables settings Advanced user options settings InForm Group 7 Edit InForm 7 InForm Group 8 Edit InForm 8 PIL Command Figure 2 1 Main Menu Models 6 The GENTRA User Guide TR 211 GENTRA User Guide Turn GENTRA on by clicking on OFF next to Lagrangian Particle Tracker GENTRA A new button labelled Settings will appear To enter the GENTRA Menu click on Settings 2 2 3 When to call the GENTRA menu As pointed out in Section 2 2 1 the GENTRA menu is used to specify data for the disperse phase the user must additionally specify the data for the continuous phase This can be done in any of the ways that are available in PHOENICS for instance a By using another menu system such as the Main Menu b By entering the PIL commands directly in the Q1 file or c By loading a case from the PHOENICS Input Library The provisions made by the GENTRA menu will depend on the continuous phase set up for instance the auxiliary storage allocated by the GENTRA menu for the GENTRA EARTH run wi
106. n Subsection c above f Data for vaporising droplets Domain Settings j 2 GENTRA Data for vaporising droplets Previous panel Drag coefficient GDRAG GRND1 Nusselt number GHUSS Cp of continuous phase GCPCON 1007 000 Cp of Vapour GCPVAP GRND1 Cp of particle GCPLIQ 4131 800 Latent heat of evaporation GLATVP GRND1 Particle liquid saturation enthalpy GHLIQD GRND1 Saturation temperature GVAPST GRND1 Saturation pressure GSTPRE GRHD1 Thermal conductivity of continuous phase GKONC 0 026300 Thermal conductivity of Vapour GKONV GRHD1 Mol Weight of continuous phase GMWCOH 28 90000 Mol Weight of particle phase GMWVAP 18 00000 Minimum particle diameter GDTRCT 0 000000 Gravity buoyancy PIL Command Page Dn Line Dn Figure 2 11 Data for vaporising droplets e Drag coefficient See Subsection c for explanation Nusselt number See Subsection d for explanation Cp of Continuous phase The default value of 1007 is for air at STP of Vapour The value of CV is defaulted to GRND1 which directs control to GPROPS where a temperature dependent property is specified Cp of Particle The default value of 4131 8 is for water e Latent heat of evaporation A saturation temperature dependent function for the latent heat of evaporation is provided as the default value GRND1 The function is for water vapour and is derived from curve fits on steam tables e Pa
107. n special data files These three categories are dealt with in the next subsections 35 The GENTRA User Guide TR 211 GENTRA User Guide 4 3 4 Screen information During the GENTRA EARTH run a message will be written to the screen when the track for a particle starts and another message will flag the end of the tracking and inform of the particle fate Between the beginning and end of track flags the following information is provided on the screen e Number of time steps for the particle e Average number of time steps per cell and e Minimum maximum and average size of the time step Error and warning messages are also routed by GENTRA to the screen All the output described in this section can be re directed to a file see Chapter 5 and Section C 3 for details 4 3 2 The RESULT file GENTRA itself does not print any information in the RESULT file but the following PHOENICS quantities provided by EARTH are related to GENTRA calculations a The values of MOMX MOMY are the interphase sources of momentum for each cell b the values of HEAT are the cell values of the interphase source of heat for heat exchanging particles c the values of MASS are the cell values of the interphase source of mass for mass exchanging particles and d if the computation of particle cell residence times is requested by the user these will be found for each cell under the variable REST 4 3 3 Special data files Two sp
108. nd The mark was assumed and the calculation continues Warning number 009 Variable out of range Variable var Value value Valid range range Explanation Variable var was supplied a value which is not within the permissible range Warning number 010 FALSDT relaxation not available for source name The source is left unrelaxed Explanation False time step FALSDT relaxation was specified for the inter phase source indicated in the warning message Since only linear relaxation LINRLX is allowed for the sources the source in question was left unrelaxed by GENTRA 72 The GENTRA User Guide TR 211 GENTRA User Guide D 3 Error messages Error number 301 Mass transfer active but MASS not STOREd Explanation Mass transfer between particles and gas was activated in the GENTRA menu but the user has not STOREd the variable MASS in the Q1 file Remedy STORE MASS in the Q1 file This is done automatically by the GENTRA menu when the particle type chosen by the user entails mass transfer Error number 302 Invalid particle type GPTYPE Explanation An invalid particle type was specified through the variable PIL variable GPTYPE Remedy See the information on GPTYPE in the GENTRA User Guide or through the menu for a list of available particle types Error number 303 NCRT must be 1 Explanation In BFC cases the PIL variable NCRT the sweep frequency for the calculation of t
109. ng this menu The panel in figure 2 15 shows all of the possible treatments Select wall treatment ES xj Remove particle a Stick particle Bounce particle Flash vaporise zl OK 1 Figure 2 15 Wall obstacle treatment The menu Wall obstacle treatment has in the general case the following options figure 2 15 Remove particle from domain On hitting a wall or obstacle the particle will be removed from the domain ie the tracking algorithm will abandon the particle and move on to the next one Stick particle to the wall On hitting a wall or obstacle the particle will remain stationary but it will still undergo heat and mass transfer processes if the particle type allows for these Note that REMOVE PARTICLE and STICK PARTICLE have the same effect for isothermal particles Bounce particle off the wall On hitting a wall or obstacle the particle will be bounced A restitution coefficient must be provided The restitution coefficient is the absolute value of the ratio between the velocity component normal to the wall before and after the contact The restitution coefficient must be greater than 0 and less than or equal to 1 See Section 6 6 2 for more information on bouncing m Choose Bounce and set a restitution coefficient of 0 75 for the worked example Then return to the previous panel Flash vaporisation On hitting a wall or obstacle the particle will be vaporised instantly and all the mass w
110. ngs with numbers between 001 and 299 which do not abort the program but reset some of the user supplied parameters that are detected to be inconsistent Fatal errors with numbers between 300 and 599 which abort the program Internal errors with numbers between 600 and 899 which should be referred to CHAM By default all the error messages are written to the screen but you can change this in the GENIUS subroutine Section 5 3 below provides details Explain PIL Variable As an alternative to the menu users can also specify the GENTRA settings using a subset of PIL variables see Chapter 3 for details Enter a variable name then click Explain Concise reference information will be displayed The information provided is summarised in Appendix B of this Guide Previous panel This option returns the user to the previous menu panel This button is common to all the GENTRA menu panels If you are following the worked example you can now explore all these sources of information if you so wish and return to the GENTRA main menu 2 5 Particle type The option Particle type of the Main Menu figure 2 2 allows you to specify the type of particle 0 vaporising droplet melting particle etc and the physics of the particle type e g drag law specific heat buoyancy effects turbulent dispersion When you choose this option the menu panel in figure 2 4 is produced The options in the panel are now dealt with in succes
111. ngs will be found in Groups 7 13 and 17 of the Q1 file A complete list of the actions undertaken by the GENTRA Menu can be found below for the user s reference a If the grid is a BFC one and the continuous phase Cartesian velocity components UCRT VCRT WCRT have not been STOREd a STORE command will be issued GENTRA uses the Cartesian velocity component for the integration of the particle momentum equations b For BFC grids NCRT ie the sweep frequency for the calculation of the Cartesian components in a is set to 1 c 3D storage space is allocated through STORE commands for the following quantities MOMX MOMY MOMZ the interphase sources of momentum Not stored for lazy and stubborn particles HEAT the interphase source of heat stored if the particle is exchanging heat with the continuous phase MASS the interphase source of mass stored if the particle is exchanging mass with the continuous phase d The variable VAPO representing the vapour mass fraction in the continuous phase for vaporising droplets is SOLVEd for if appropriate and its PRANDTL numbers PRNDTL VAPO laminar and PRT VAPO turbulent are assigned according to the menu settings e If the calculation of cell residence time for a particle has been requested 3D storage is allocated for the variable REST through a STORE command f PATCHes and COVALs are generated for the interphase sources as follows PATCH
112. ns in this panel can be divided into two groups e The first group includes options for the entry of data of four kinds e Particle physics boundary conditions for particles e numerical controls and e input output controls e The second group with just one option gives access to general information on GENTRA and the menu 7 The GENTRA User Guide TR 211 GENTRA User Guide The options in these groups will now be explained in this manual Section 2 4 below will explain what help and information are available on line Sections 2 5 to 2 9 will deal with the first group i e data entry and Section 2 10 will explain how to finish the menu session Domain Settings i E E 2 x GENTRA Main Menu Previous panel Particle type Boundary conditions for particles Numerical controls I 0 controls Help and information PIL Command Figure 2 2 The main menu panel 2 4 Help and information The option Help and information of the Main Menu figure 2 2 brings up the menu panel shown in figure 2 3 Domain Settings EU 3 xl GENTRA Help Previous panel How to obtain HELP in the menu General Information GENTRA Glossary Known limitations of GENTRA Explain run time error number IX1 0 Explain Explain GENTRA pil variable CX1 Explain PIL Command Figure 2 3 Help and information The options in this panel are explained below How to obtain help in the menu Help in the GENTR
113. olid for solidifying melting particle C gprops heat capacity of solid C paramt particle temperature ENDIF C END OF GROUND 1 C C G GROUND as Examples C Example functions used for testing and validation C ELSEIF GRNDNO 2 DEFVAL THEN IF FUNAME EQ 5 THEN C C 5 Latent heat of solidification 2 gprops latent heat of solidification paramt particle temperature 5 1 31 ELSE I FUNAME 06 1000 0 PARAMT EQ 8 THEN 99 The GENTRA User Guide TR 211 GENTRA User Guide C 8 Heat capacity Cp of the particle E gprops heat capacity of the liquid paramt liquid temperature Kelvin GPROPS 1000 0 0 1 PARAMT ENDIF GROUND X ELSEIF GRNDNO X DEFVAL THEN Properties for other materials can be added in exactly the same way as for water X is from 1 to 10 and GRNDX should be given to the request property as default in 01 ENDIF ENDIF C END C F FINDGR GPROPS THEN WRITE BUFF A I2 A GPROPS FUNAME is required but no constant or function has been supplied CALL PRINT CHECK BUFF 1 LUPRO CALL GWYOUT 2 ENDIF if dbglev and dbgrnd call writlr gprops gprops ND ob 100 The GENTRA User Guide TR
114. ollowing generalized form d q 6 29 where amp represents the variable to be solved momentum mass or enthalpy and A and B are constants The equation is integrated over the Lagrangian time step such that the value at the end of the time step amp 1 can be expressed in terms of the value at the start of the time step 9 and the constants A and B thus n 2 Lg 6 30 If the constant B in equation 6 29 is zero implying that the rate of change of amp is independent of the value of amp the use of equation 6 30 would result in division by zero Hence in this case equation 6 29 is integrated thus EN 0 AAt 6 31 The form of the constants in equation 6 29 is dependent on the equation being solved In the following subsections the method of integration for each of the particle equations will be presented The particle momentum equation The particle momentum equation equation 6 3 may be expressed in the form of equation 6 29 as 6 32 P _ DpUg Dp dt Mp DI p Up from which the constants A and B of equation 6 29 can be seen to be D 0 Ug bg Vp 6 33 2 D B 6 33b mp The particle mass equation For the case of a particle evaporating in a constant environment and at constant temperature the rate of change of particle surface area with time is constant This is taken into account in the met
115. olved variabl SOLVE P1 TR 211 GENTRA User Guide Stored variabl REST NAME 144 MOMZ MOMY NAME 146 NPOR VPOR NAME 148 WCRT VCRT NAME 150 UCRT es list V1 W1 es list STORE UCRT VCRT WCRT VPOR NPOR MOMY MOMZ REST Additional SO ver options SOLUTN P1 CkCckCckck ck ckckck ck ck ckck kk kk C CK CC CC CC CC CC CC CC CC CI C Ck kk kk Sk ke E ko ko ko ko ko ko Group 8 Terms amp Devices DIFCUT 0 000000E 00 Ck Ck EAER kk kkk Ek kkk kkk ck ck Ck Sk Sk Sk Sk ck kk ko ok ko Sk ko ck kx ko kkk Group 9 Properties RHO1 1 000000E 03 ENUL 1 000000E 06 CP1 1 000000E 00 ENUT 1 000000 04 kk Ckckck ck ckck kk X Group 10 Ckckck ck ck ck kk X Initiali Group W1 VPOR 1 p PO T NIT NIT No P N ADD VCRT ATCHes used 000000 00 0000001 001000 10 C CK CC CC CC CK CC CC CC CIC CC C kk kk kk ko ko ko ko kx ko ko ko ko Inter Phase Transfer Processes di dio div dir dio di dio dio di di dio dio di di dio di di di di dir di di dio dir dio di dir dio di die dir dio di di die dio di dir di di di dio di di di diri se Var Porosity Fields FIINIT NPOR 1 000000E FIINIT WCRT 1 001000 FIINIT UCRT
116. on Dp used in GENTRA has the following form 1 Dp 5 p Ap Cp U Up 6 4 where Tdp Ap is the particle projected area FT 6 5 Cp is the drag coefficient which by default is given by 0 42 24 EEA T pu 0440 Gp gg 1 0 15 Fo 7 7 5 408104 Re 116 Re 6 6 where Re is the particle Reynolds number This correlation provided by Clift Grace and Weber 1978 is valid for rigid spherical particles and Re lt 3x10 6 3 3 The particle mass equation The evolution of the mass of the particle mp is described by the particle mass equation thus dm k Ts zdp Nu In 1 Ba 6 7 where dp is the diameter of the particle ky is the thermal conductivity of the vapour produced by the evaporation of the droplet Cpy is the specific heat capacity of that vapour Nu is the Nusselt number determined from the following correlation Nu 2 1 0 3 Re 5 Pr0 33 F 6 8 47 The GENTRA User Guide TR 211 GENTRA User Guide where Pr is the laminar Prandtl number for the continuous phase and F is the Frossling correction for mass transfer given by Faq By In 1 Bu 6 9 BMis the mass transfer number which represents the driving force in the mass transfer process and is defined by Yvs BM 6 10 M 1 5 where Yvs is the mass fraction of vapour at the surface of the droplet and Yyoo the mass fraction of vapour in the gas surrounding the droplet The
117. oned a timeout message is issued and GENTRA moves on to the next particle This device can avoid large computing times arising for instance from particles being trapped in recirculation regions The timeout value r can be positive negative or zero e r gt 0 abandons the tracking after the particle has been tracked for seconds e r 0 deactivates this timeout device e r 0 indicates that the timeout limit is to be applied in each cell i e the timeout counter is reset when the particle enters a new cell Enter 10 for the worked example Since the fluid inlet velocity is 2 0 m s and the domain length in that direction is 2 m the particles can be expected to have left the domain in that time Relaxation factor for sources This option allows the user to specify a linear relaxation factor a real number between 0 and 1 for the sources that account in the continuous phase equations for the transfer of momentum mass and thermal energy from the particles Values between 0 and 1 have the effect of setting the source to be a weighted average of the sources calculated at the current and previous sweeps i e So ASO 1 5 1 26 The GENTRA User Guide TR 211 GENTRA User Guide This may be beneficial for the convergence of the continuous phase solution when the source is changing significantly from sweep to sweep e a value of 1 applies no relaxation to the source ie only the source calculated at the current
118. placed by a particle temperature dependent function in GPROPS A constant value of 1007 J kg k is provided as the default value for the specific heat capacity of the continuous phase this being the value for air at STP The constant value can be altered during the menu session or a temperature dependent function can be implemented using the techniques mentioned above 16 The GENTRA User Guide TR 211 GENTRA User Guide Gravity and buoyancy pressure gradient effects and turbulent dispersion can be included the reader is referred to the entries in sub sections c and a above for an explanation e Data for melting solidifying particles Domain Settings D KA GENTRA Data for melt solidif particle Previous panel Drag coefficient GDRAG GRHD1 Thermal conductivity of continous phase GKONC 0 026300 Nusselt number GHUSS iGRHDL Cp of liquid GCPLIQ 4131 800 Cp of solid GCPSOL 4131 800 Cp of continuous phase GCPCON 1007 000 Latent heat of solidification GLHEAS 333500 0 Index for solid frac formula GSOLIN 1 000000 Solidus temperature GSOLST 273 1500 Liquidus temperature GLIQST 273 1500 Gravity buoyancy Stochastic turbulence model gactiv Currently NOT ACTIV PIL Command Figure 2 10 Data for melting solidifying particles The data required for melting solidifying particles is as follows Drag coefficient see Subsection c for explanation Thermal conductivity of continuous phase Th
119. produce trajectory files for all five particles being tracked Therefore input a suitable character with which the file names should commence say T We require trajectory files for each of the first five particles so select the first and last particles as 1 and 5 respectively Now select Previous panel twice to return to the I O controls menu panel Note that a maximum of 20 trajectory and 20 history files can be created in this way Trajectory and history information for all particles is held in the global history file see figure 2 18 and Appendix 2 9 2 Restart file name The name of the GENTRA restart file Up to 4 characters can be used This option is not relevant to steady state cases In a transient case it is the name to which GENTRA writes the particle information at the end of the last time step This can then be used to continue the run 2 9 3 Cell residence time and particle volume fraction calculation This option in the Output control panel selects a particle for which the cell residence time will be calculated by GENTRA The particle is identified by the user through the particle number In addition to the particle number two special numbers can be used as flags to perform special functions O will deactivate the calculation of residence time 1 will add the residence time of all the particles in each cell 2 will activate the calculation of a particle volume fraction for each cell representing the fraction of
120. qual to a GROUND number control will be directed within GPROPS to the appropriate section where it will be set as a function of PARAMT It is possible to set GPROPS to be a function of any of the variables within GENTRA described in Appendix C as these are available within GPROPS due to the inclusion of the common file TRACMN If a GROUND number is set for DEFVAL but appropriate coding is not supplied within GPROPS an error condition will occur and execution of GENTRA EARTH will be stopped 5 5 Building private versions of GENTRA After modifying a user accessible module of GENTRA i e subroutines GENTRA GENIUS or GPROPS the user must build a private version of EARTH The build script will automatically compile GENTRA HTM so there is no real need to compile it separately In the VR Environment click on Build then Earth PHOENICS VR Editor File Edit View Run Options Compile Bud Demos Help j Earth Satelite Photon iter Figure 5 3 Building a Private EAREXE Once the new EARTH executable has been built the environment must be told to run the private EARTH not the public CHAM supplied EARTH Click on Options Run version then select Private or Prompt for Earth PHOENICS VR Editor Fie Edit View Run Options Compile Build Demos Help alm 5 Monitor Options Run Version Satelite gt File Format Public Change Working Directory Photon
121. rature of cont phase as a function of enthalpy gprops temperature of the continuious phase paramt enthalpy of the continuous phase GPROPS PARAMT GCPGAS ELSEIF FUNAME EQ 7 THEN 7 Enthalpy of cont phase as a function of temperature gprops enthalpy of the continuous phase paramt temperature of the continuious phase GPROPS PARAMT TMP1A TMP1B ELSEIF FUNAME EQ 8 THEN I 8 Heat capacity Cp of the particle Cp of liquid for melt solidif particle gprops heat capacity of the particle 96 The GENTRA User Guide 0000020 000020 OIRO Ri CQ CY C3 OO CX C3 0000020 2000000020 a TR 211 GENTRA User Guide Cp of liquid for melt solidif particle paramt particle temperature Kelvin XPARAM PARAMT 273 15 GPROPS 3892 438 XPARAM 3 14895 93 XPARAM 2 18779 6 XPARAM 11993 33 ELSEIF FUNAME EQ 9 THEN 9 Latent heat of evaporation gprops latent heat of evaporation paramt temperature of the particle Derived from curve fit on steam tables T in Kelvin 5 6 2909 06 2 7457E 4 PARAMT 65 991 PARAMT 2 5 7653E 2 PARAMT 3 I ELSEIF FUNAME EQ 10 THEN 10 Solid fraction gprops solid fraction paramt temperature of the particle GPROPS 0 0 GBASE GTLIQD PARAMT GTLIQD GTSOLD
122. rent PHOENICS session C The property index used to identify solid region INTEGER C in conjugate heat transfer cases Consult CHAM if uncertain PRINDX 100 IF IGENSC EQ 1 THEN e K Section 2 Beginning of current Eulerian time step ELSEIF IGENSC EQ 2 THEN ENDIF 91 The GENTRA User Guide TR 211 GENTRA User Guide C C GROUP 2 Start of new track ELSEIF IGENGR EQ 2 THEN C GROUP 3 Start of new Largrangian time step for the current track C ELSEIF IGENGR EQ 3 THEN IF LG 30 THEN F IP EQ 1 THEN UCPARN 0 0 VCPARN 0 73 UCGASN ELSEIF IP EQ NTRACK THEN UCPARN UCGASN VCPARN 0 ENDIF ENDIF C GROUP 4 Particle reaches cell boundary C ELSEIF IGENGR EQ 4 THEN C C GENSC values as follows 1 Exit 2 Wall 3 Axis or symmetry surfac 4 New cell C C GROUP 5 End of the current Lagrangian time step C ELSEIF IGENGR EQ 5 THEN C C GROUP 6 End of current track ELSEIF IGENGR EQ 6 THEN C GROUP 7 GENTRA returns control to Earth ELSEIF IGENGR EQ 7 THEN C GROUP 8 Special calls
123. rticle identified by its number lt ip gt was initially an incorrect one e g outside the computational domain or in a blocked region The particle was skipped Remedy Specify a correct initial position in the inlet data table Warning number 006 Error reading inlet data in line line Not enough or too many data items for this particle Read read Needed needed The data line has been ignored Explanation A inlet data line had a number of data items different from that required the line was ignored The line the number of data items read and the number of data items needed are displayed The number of inlet data items needed for each particle varies from case to case a suitable heading for the table is provided for your guidance in the Q1 file by the GENTRA menu 71 The GENTRA User Guide TR 211 GENTRA User Guide Warning number 007 Error reading inlet data in line line Line discarded Explanation A inlet data line could not be read correctly The likely causes of this warning are 1 character was used instead of a number e g letter O instead of number zero 2 comment line was included in the table but without an asterisk A A Warning number 008 Inlet data from Q1 but no lt END GENTRA INLET gt mark Mark assumed Explanation When reading inlet data from the Q1 file the lt END GENTRA INLET gt mark which flags the end of the inlet data table was not fou
124. rticle liquid saturation enthalpy The default value of GRND1 produces a temperature dependent function for the liquid saturation enthalpy of water based on curve fits from steam tables e Saturation temperature of vapour The default value of GRND1 provides a function for the saturation temperature of water vapour as a function of pressure e Saturation pressure of vapour The default value of GRND1 provides the temperature dependent vapour pressure correlation of Bain 1964 e Thermal conductivity of continuous phase The default value of 0 0263 is for air at STP e Thermal conductivity of vapour The default value of GRND1 provides a temperature dependent function for water vapour based on curve fits to steam tables e Molecular weight of continuous phase defaulted to air 28 9 18 The GENTRA User Guide TR 211 GENTRA User Guide Molecular weight of particle phase defaulted to water 18 0 Minimum particle diameter The minimum size of particle below which the particle is assumed to have completely evaporated Gravity buoyancy pressure forces See Subsection c above for details on this option Stochastic turbulence model See Subsection a above for details on this option This option appears on the next panel reached by clicking Page down or Line down The constant values which appear in this menu can be replaced with functions set in function routine GPROPS according to the method described in Subsection c
125. s is explained in Appendix H Coordinate system for Velocities Option not available in the present version of GENTRA This option allows the specification of inlet velocities in the inlet file in either the GENTRA Cartesian system see glossary entry for a definition or in the grid system The distinction is only relevant to cylindrical polar and BFC grids since in Cartesian grids the velocity components in the GENTRA Cartesian system and in the grid system are the same At present all inlet velocities must be specified in the Cartesian co ordinate system in the order Ucrt Vcrt Wcrt where these represent the velocity components in the Cartesian X y and Z directions respectively For cylindrical polar grids the order of specification is Vert Ucrt and Wert 20 The GENTRA User Guide TR 211 GENTRA User Guide 2 7 1 1 Format and contents of the inlet data table Inlet data In the inlet data table each parcel of particles has a data line the data required is case dependent For the user s guidance the GENTRA menu will generate as a comment in the resulting Q1 file a suitable heading for the inlet table The contents of the inlet table are also provided below for the different particle types Properties required Lazy POSTN POSTN VELOC DIAM DENSTY FRATE NUMB Heat POSTN VELOC DIAM DENSTY FRATE TEMP NUMB exchanging Melt solidifying POSTN VELOC DIAM LIQDEN FRATE TEMP SOLDEN NUMB POSTN VELOC DIAM DE
126. s phase velocity and is a turbulent velocity fluctuation calculated from the local turbulence conditions when the stochastic turbulence model is activated Stubborn particles For stubborn particles the particle velocity is constant and equal to the value prescribed at the inlet Up constant 6 3 2 The particle momentum equation The velocity of the particle Up is computed from the particle momentum equation dU 52 Dp U Up mp b g Vp Vp 6 3 where mp is the mass of the particle Dp is a drag function to be defined below U is the continuous phase instantaneous velocity U Uc Uc Uc is the continuous phase average velocity and is a turbulent fluctuation which is added if the stochastic turbulence model is active see Section 6 4 1 46 The GENTRA User Guide TR 211 GENTRA User Guide g isthe gravitational acceleration b is a buoyancy factor equal to 1 if the buoyancy option is active or to 1 0 p otherwise Vp is the particle volume and Vp is the continuous phase pressure gradient The first term on the right hand side of equation 6 3 represents the drag force exerted by the continuous phase on the particle and the second represents the gravitational force Source terms accounting for the virtual mass and Basset forces Saffman lift and Magnus forces are neglected The conditions under which these source terms can be neglected have been given by Faeth 1983 The drag functi
127. s that are tracked It can be post processed using the UNPACK program to produce individual history and or trajectory files Details of the operation of the UNPACK program can be found in Appendix K e Output for Individual particle The panel of figure 2 19 will follow if this option is selected We will require individual trajectory files so choose this option Domain Settings de E 21 GENTRA Output for individual particle Previous panel ID of indiv History file GH1ISTC Currently rones 7 ID of indiv Trajectory file GTi1STC Currently 7 First trajectory to write NGWSTR Currently 0 Last trajectory to write NGWEND Currently 0 Interval of writing trajectories NGWINT Currently 1 PIL Command Figure 2 19 Output for individual particle e ID of Indiv history file the first character for the name of the individual history file 28 The GENTRA User Guide TR 211 GENTRA User Guide e ID of Indiv trajectory file the first character for the name of the individual trajectory file e First trajectory to write the first track for which an individual history trajectory file is required e Last trajectory to write the last track for which an individual history trajectory file is required e Interval of writing trajectories at which the individual history trajectory file is written between the two tracks selected in the last two options In this worked example we would like to
128. sive subsections Click on Particle type now 9 The GENTRA User Guide TR 211 GENTRA User Guide Domain Settings B x GENTRA particle type Previous panel Current type ISOTHERMAL PARTICLES settings PIL Command Figure 2 4 Particle type The particle type to be simulated is selected by clicking on the name of the particle type which by default is Isothermal Particles This displays a list of available particle types shown in Figure 2 5 The settings button allows the specification of the physics and data of the chosen particle type Finally there is an option to return to the previous menu EE GENTRA particle type Previous panel Current type ISOTHERMAL PARTICLES settings Lazy particles Stubborn particles Stubborn heat transfer Stubborn vaporisation Isothermal particles Heat exchanging particles Melting solidifying particles Vaporising droplets Figure 2 5 Particle type selection For the worked example the isothermal particle type should be selected The number of inputs for this particle type is small but permits the typical features of all panels to be examined e Lazy particles Vpart Vfluid Lazy particles do not have a velocity of their own but share at each point the continuous phase velocity They therefore behave like tracers 10 The GENTRA User Guide TR 211 GENTRA User Guide Lazy particles do not have a size or a temperature and cannot undergo any physical process
129. the cell volume occupied by particles See Section 6 6 4 for additional details m Choose as an example to compute the residence time for particle number 2 Remember that you will define the particle inlet data after the menu session When choosing a value different from 0 the GENTRA menu will automatically allocate whole field storage space for the variable REST through the command STORE REST The variable REST will be used by GENTRA to store the cell residence time this can be inspected in the printout of that variable in the RESULT file The foregoing options are available for steady flows only STEADY T and the particle volume fraction option is not available for lazy particles GPTYPE 10 because the particle mass is zero For unsteady flow STEADY F the particle volume fraction will be calculated for each cell see section 6 6 4 provided that STORE PVFR appears in the Q1 input file 29 The GENTRA User Guide TR 211 GENTRA User Guide 2 9 4 Particle mass concentration calculation This option in the Output control panel provides for the calculation of the particle mass concentration for each cell see Section 6 6 5 It can also be activated by setting STORE PMCO in the Q1 input file 2 9 5 Mixture density calculation This option in the Output control panel provides for the calculation of the mixture density for each cell see Section 6 6 6 It can also be activated by setting STORE RHMX in the Q1 input file 2 9
130. the next one It is visited after the plot trajectory and history files have been written if appropriate and closed 5 3 7 GENIUS Group 7 GENTRA returns control to EARTH GENIUS Group 7 is visited immediately before RI CALL to GENTRA for the current sweep 5 3 8 GENIUS Group 8 Special calls Group 8 of G There are 5 sections in this group e Section 1 Particle momentum equation ETURNing the control to EARTH after the ENIUS is designed to allow the user to modify the built in Lagrangian equations The method of discretization of the particle momentum equation is described in Section 6 5 3 The discretized form of the equations is U dt Wp Wg gd UP g Up GVCSCX Vp GVCSBB Vg GVCSAA Vp GVCSCY Wp GVCSCZ At the time this section is called all of the coefficients and sources GVCSAA GVCSBB GVCSCX GVCSCY GVCSCZ have been calculated in GENTRA For the particle momentum equation given by equation 6 32 in Section 6 5 3 the prevailing values are GVCSAA GVCSBB GVCSCX b g L sdpiax p P GVCSCY b gy dp dy p P 41 The GENTRA User Guide 5 3 9 TR 211 GENTRA User Guide GVCSCZ b g L sdpidz P Users are free to reset them or add to them For example if an extra magnetic field needs to be taken into account and the effect of the magnetic force on the particle can be written as dup _ dx GMX if only x
131. troduction This chapter lists all the GENTRA PIL variables with their type default value and if appropriate units and valid range of values the latter enclosed in angle brackets lt gt See Chapter 3 for background information on the GENTRA PIL In addition to being used in the Q1 file all these variables are also available in the FORTRAN subroutine GENIUS through the COMMON blocks INCLUDEd in TRACMN Information on each of these variables is also available through the GENTRA Menu See Section 2 5 B 2 List of variables B 2 1 GENTRA Group 1 Particle physics Variable Type Meaning B 2 2 GENTRA Group 2 Boundary conditions Variable Type Meaning Cd GINFIL CHAR Name of the file for particle inlet condition GINSYS Co ordinate system for particle inlet condition GPOROS REAL Threshold for obstacle porosity GWALLC Wall type GWREST REAL Restitution coefficient of wall 62 The GENTRA User Guide TR 211 GENTRA User Guide B 2 3 GENTRA Group 3 Numerical controls Variable Type Meaning B 2 4 GENTRA Group 4 Output controls Name Meaning 1 Frequency time steps for output 63 The GENTRA User Guide TR 211 GENTRA User Guide Appendix C List of GENTRA FORTRAN variables The main GENTRA variables are listed in this Appendix These variables are available through the common blocks in the file TRACMN copy of which
132. turn to the previous panel by clicking Previous panel The gravity buoyancy forces option enables the user to activate gravity forces for the particles and to include buoyancy and pressure gradient effects The option brings up the menu panel displayed in figure 2 8 14 The GENTRA User Guide TR 211 GENTRA User Guide Domain Settings MES GENTRA Gravity buoyancy Previous panel X component of gravity vector Currently 0 000000 component of gravity vector Currently 0 000000 Z component of gravity vector Currently 0 000000 Force on particle due to buoyancy GBUOYA Currently HOT ACTIVE Force on particle due to pressure gradient GSURPR Currently HOT ACTIVE PIL Command Figure 2 8 Gravity ouoyancy e X Y Z component of gravity vector Use these options to specify the three components of the gravitational acceleration acting on the particles The components of the gravitational acceleration must be supplied in the GENTRA Cartesian System regardless of the co ordinate system being employed for the continuous phase See entry in the GENTRA glossary for a description of the GENTRA Cartesian System Enter 9 8 for Z component of gravity vector to specify an acceleration of 9 8 m s acting along the z axis e Force on particle due to buoyancy This option activates deactivates the buoyancy formulation When active it introduces a multiplicative factor 1 in the gravity term of the particle momentum equation See Se
133. umvent the need to use the menu Chapter 4 Running GENTRA EARTH explains how to execute the flow solving program EARTH Chapter 5 The GENTRA FORTRAN explains how experienced users can use the open code area of GENTRA EARTH to supplement the built in numerical and physical features Chapter 6 The GENTRA Equations contains a complete listing of the mathematical models embodied in GENTRA and some details of the numerical techniques used for the solution of the equations Appendix A lists the main limitations of GENTRA Appendix B lists the GENTRA PIL variables Appendix C lists the user accessible variables in the FORTRAN of GENTRA Appendix D is a compilation of the GENTRA run time errors Appendix E has a listing of the Q1 file resulting from the worked example in Chapter 2 Appendix F has a listing of the contents of the GENTRA Input Library Appendix G contains a listing of the user accessible subroutine GENIUS Appendix H is a glossary of the terms used in this manual Appendix is a list of references Appendix J contains a list of the nomenclature Finally Appendix K provides information on setting up GENTRA 4 The GENTRA User Guide TR 211 GENTRA User Guide 1 6 Conventions used in this Guide The following conventions are used in this Guide e The bold typeface is used for menu titles menu options and also for PIL variables e The Courier typeface is used for FORTRAN variables and commands e A pointing hand
134. y the cell indexes 1 PAR since these will be found by GENTRA using the particle co ordinates supplied 5 3 3 GENIUS Group 3 start of new Lagrangian time step for the current track Group 3 of GENIUS is visited at the beginning of the time step after e the time step counter JCOUNT has been updated e the particle properties at the beginning of the current time step are assigned the values prevailing at the end of the previous one e continuous phase properties at the particle position have been found see Section C 1 for a list of these variables and Section 6 8 3 for further information and e the stagnation check has been passed see Section 6 8 1 and before e time step is calculated see Section 6 7 1 and e the particle is moved see Section 6 8 Users can in this group specify the maximum time step by resetting the variable GDTMAX initially set in the Q1 file menu or inspect and with caution change the continuous phase properties experienced by the particle see Section 6 8 3 5 3 4 GENIUS Group 4 Particle reaches cell boundary GENIUS Group 4 is visited when a particle reaches a cell boundary The value of IGENSC is used to distinguish between several events as follows GENSC 1 means that the particle has reached an exit i e the appropriate face of a patch whose name starts with GX GENSC 2 means that the particle has reac

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