fluent多相流算例

1、Dam-BreakSimulationUsingFLUENTsVolumeofFluidModel cFluentInc.November6,2006 #cFluentInc.November6,2006 cFluentInc.November6,2006Tutorial:Dam-BreakSimulationUsingFLUENTsVolumeofFluidModelPurposeThistutorialexaminesthedam-breakproblemusingtheVolumeofFluid(VOF)multiphasemodel.Thistutorialdemonstratesho

2、wtodothefollowing:Setupadam-breakproblem.Choosethetimestepbyestimatingthemaximumpossiblevelocityoftheinterfaceandthegridcelldimension.SolvetheproblemusingtheVOFmodel.Manipulatethesolutionparameters.PrerequisitesThistutorialassumesthatyouarefamiliarwiththeFLUENTinterfaceandthatyouhaveagoodunderstandi

3、ngofbasicsetupandsolutionprocedures.Inthistutorial,youwilluseVOFmultiphasemodel,soyoushouldhavesomeexperiencewithit.Thistutorialwillnotcoverthemechanicsofusingthismodel;instead,itwillfocusontheapplicationofthismodeltosolveadam-breakproblem.Ifyouhavenotusedthismodelbefore,itwouldbehelpfultofirstrefer

4、totheFLUENT6.3UsersGuideandtheFLUENT6.2TutorialGuide.ProblemDescriptionTheinitialsetupofthedam-breakproblemisshowninFigure1.Inthisproblem,arectangularcolumnofwater,inhydrostaticequilibrium,isconfinedbetweentwowalls.Gravityisactingdownwardswithamagnitudeof-9.81m/s2.Atthebeginningofthecalculation,ther

5、ightwallisremovedandthewaterisallowedtoflowouttothehorizontalwall.1.00e+009.50e-019.00e-018.50e-018.00e-017.50e-017.00e-016.50e-016.00e-015.50e-015.00e-014.50e-014.00e-013.50e-013.00e-012.50e-012.00e-011.50e-011.00e-015.00e-020.00e+00ContoursofVolumefraction(water-liquid)(Time=0.0000e+00)FLUENT6.3(2

6、d,pbns,vof,lam,unsteady)Figure1:InitialSetupoftheProblemPreparationCopythemeshfile,dambreak.msh.gztotheworkingfolder.Startthe2D(2d)versionofFLUENT.Dam-BreakSimulationUsingFLUENTsVolumeofFluidModel cFluentInc.November6,2006 cFluentInc.November6,2006 #cFluentInc.November6,2006SetupandSolutionStep1:Gri

7、dReadthegridfiledambreak.msh.gz.Checkthegrid.Grid-CheckDisplaythegrid(Figure2).Display-Grid.ClicktheColors.buttontoopentheGridColorspanel.SelectColorByID.Thiswillassignadifferentcolortoeachzoneinthedomain,ratherthantoeachtypeofzone.ClosetheGridColorspanel.ClickDisplay.ClosetheGridDisplaypanel.GridFL

8、UENT6.3(2d,pbns,lam)Figure2:GridDisplayStep2:ModelsDefinethesolversettings.Dene-tModels-Solver.SelectUnsteadyforTime.ClickOKtoclosetheSolverpanel.Definethemodelsettings.Deine-tModels-tMultiphase.SelecttheVolumeofFluidmultiphasemodel.EnableImplicitBodyForceFormulation.ClickOKtoclosetheMultiphaseModel

9、panel.Step3:MaterialsThedefaultpropertiesofwaterandairarethecorrectvaluesforthisproblem.YoucancheckthemintheMaterialspanel.Definethematerialproperties.Deine-tMaterials.Retainthedefaultsettingsforair.Definethenewmaterialbycopyingwater-liquid(h20)fromtheFluentDatabase.ClickChange/CreateandclosetheMate

10、rialspanel.Definetheprimary(air)andsecondary(water-liquid)phases.Deine-tPhases.Specifyairastheprimaryphase.Specifywater-liquidasthesecondaryphase.ClosethePhasespanel.Step4:OperatingConditionsDene-OperatingConditions.EnableGravity.Enter-9.81m/s2forGravitationalAccelerationintheYdirection.EnableSpecii

11、edOperatingDensityandretainthedefaultvalueforOperatingDensity.ClickOKtoclosetheOperatingConditionspanel.Step5:BoundaryConditionsDeine-BoundaryConditions.Settheboundaryconditionsforpoutlet.Inthedrop-downlistforPhase,selectwater-liquidandclicktheSet.button.Retainthedefaultvalueof0forBackflowVolumeFrac

12、tion.ClickOKtoclosethePressureOutletpanel.ClosetheBoundaryConditionspanel.Step6:Solution1.Setthesolutionparameters.Solve-Controls-Solution.Enter0.9forPressure,0.7forMomentum,and1fortheremainingparametersintheUnder-RelaxationFactorsgroupbox.SelectPRESTO!fromthePressuredrop-downlist,andFirstOrderUpwin

13、dfromtheMomentumdrop-downlistintheDiscretizationgroupbox.SelectPISOfromthePressure-VelocityCouplingdrop-downlist.PISOisrecommendedfortransientflowsimulations.ClickOKtoclosetheSolutionControlspanel.SettheterminationcriteriaforPressure.Solve-Controls-Multigrid.Enter0.001forTerminationValueforPressure.

14、ClickOKtoclosetheMultigridControlspanel.Initializethesolution.SolveInitializeInitialize.RetainthedefaultvaluesforallcomponentsandclickInit.ClosetheSolutionInitializationpanel.Patchtheinitialdistributionofthewater-liquid.Solve-Initialize-Patch.Inthedrop-downlistforPhase,selectwater-liquid.IntheVariab

15、lelist,selectVolumeFraction.SelectwaterintheZonesToPatchlist.SettheValueto1.ClickPatchandclosethePatchpanel.Enabletheplottingofresidualsduringthecalculation.Solve-Monitors-Residual.EnablePlot.ClickOKtoclosetheResidualMonitorspanel.Calculatethetimestepbyestimatingthemaximumpossiblevelocityoftheinterf

16、aceandthegridcelldimension.Courant=,t，Xellvfluidfluidgh=2vf2luid2gha10m/s,t=,xen/vfiuidaO.OIsecSetthetimesteppingparameters.Solve-Iterate.Enter0.01(s)forTimeStepSize.Enter20forNumberofTimeSteps.Enter40forMax.IterationsperTimeStep.ClickApply.Savetheinitialcaseanddatafiles,(dambreak.cas.gzanddambreak.

17、dat.gz).ClickIteratetostartthecalculation.AfterFLUENTcompletesthespecifiednumberofiterations,runthecalculationfurthersuccessivelyspecifying30,30,and20(atotalof80)forNumberofTimeSteps.Savethecaseanddatafilesaftereachsetofiterations.ThiswillhelpinviewingtheprogressoftheVOFsimulation.Step7:Postprocessi

18、ngThevelocityvectorsandcontoursofvelocityfortheVOFmodelaredisplayedforfourtimestepvalues.Thefollowingfigures(Figure3toFigure9)showtheprogressionofthesolutionasthenumberoftimestepsisincreased.1.Displayvelocityvectorsafter20timesteps(Figure3).(a)SelectVelocityfromtheVectorsOfdrop-downlist.(b)Selectmix

19、turefromthePhasedrop-downlist.SelectVelocity.andVelocityMagnitudefromtheColorBydrop-downlistsandclickDisplay.Displayfilledcontoursofvolumefractionofwater-liquidafter20timesteps(Figure4).(a)SelectPhases.andVolumeFractionfromtheContoursOfdrop-downlists.(b)Selectwater-liquidfromthePhasedrop-downlistand

20、clickDisplay.Similarly,displaythecontoursofvolumefractionandvelocityvectorsafter50,80,and100timesteps(Figure5toFigure10).Dam-BreakSimulationUsingFLUENTsVolumeofFluidModel cFluentInc.November6,2006 cFluentInc.November6,2006 #cFluentInc.November6,20064.26e+004.05e+003.84e+003.62e+003.41e+003.20e+002.9

21、9e+002.77e+002.56e+002.35e+002.14e+001.92e+001.71e+001.50e+001.29e+001.08e+008.63e-016.51e-014.39e-012.26e-011.41e-02(Time=2.0000e-01)ibns,vof,lam,unsteady)VelocityVectorsColoredByVelocity皿39門(mén)峠冷呂牌電馬園島Figure3:VelocityVectorsColoredByVelocityMagnitudeafter20TimeSteps1.00e+009.50e-019.00e-018.50e-018.0

22、0e-017.50e-017.00e-016.50e-016.00e-015.50e-015.00e-014.50e-014.00e-013.50e-013.00e-012.50e-012.00e-011.50e-011.00e-015.00e-020.00e+00ContoursofVolumefraction(ater-liuid)仃ime=2.0000e-01)FLUENT6.3(2d.pbns.vof.lam,unsteady)Figure4:ContoursofWaterVolumeFractionafter20TimeSteps7.33e+006.97e+006.60e+006.2

23、4e+005.87e+005.51e+005.14e+004.78e+004.41e+004.05e+003.68e+003.32e+002.95e+002.58e+002.22e+001.85e+001.49e+001.12e+007.58e-013.93e-012.78e-02i(Time=5.0000e-01)ibns,vof,lam,unsteady)VelocityVectorsColoredByVelocity皿39門(mén)峠畐呂瞬電馬園/和Figure5:VelocityVectorsColoredByVelocityMagnitudeafter50TimeSteps1.00e+009

24、.50e-019.00e-018.50e-018.00e-017.50e-017.00e-016.50e-016.00e-015.50e-015.00e-014.50e-014.00e-013.50e-013.00e-012.50e-012.00e-011.50e-011.00e-015.00e-020.00e+00ContoursofVolumefraction(ater-liuid)(Time=5.0000e-01)FLUENT6.3(2d.pbns.vof.lam,unsteady)Figure6:ContoursofWaterVolumeFractionafter50TimeSteps

25、9.01e+008.56e+008.11e+007.66e+007.21e+006.76e+006.31e+005.86e+005.41e+004.96e+004.51e+004.06e+003.61e+003.16e+002.71e+002.26e+001.80e+001.35e+009.04e-014.53e-012.46e-03(Time=8.0000e-01)ibns,vof,lam,unsteady)VelocityVectorsColoredByVelocity皿39門(mén)峠冷呂牌電馬園島Figure7:VelocityVectorsColoredByVelocityMagnitude

26、after80TimeSteps1.00e+009.50e-019.00e-018.50e-018.00e-017.50e-017.00e-016.50e-016.00e-015.50e-015.00e-014.50e-014.00e-013.50e-013.00e-012.50e-012.00e-011.50e-011.00e-015.00e-020.00e+00ContoursofVolumefraction(ater-liuid)仃ime=8.0000e-01)FLUENT6.3(2d.pbns.vof.lam,unsteady)Figure8:ContoursofWaterVolume

27、Fractionafter80TimeSteps9.35e+008.88e+008.41e+007.94e+007.48e+007.01e+006.54e+006.08e+005.61e+005.14e+004.68e+004.21e+003.74e+003.28e+002.81e+00VelocityVectorsColoredByVelocityMagnitude(mixturei(Time=1.0000e+00)ibns.vof.lam.unsteai2.34e+001.88e+001.41e+009.41e-014.75e-017.71e-03Dam-BreakSimulationUsingFLUENTsVolumeofFluidModel #cFluentInc.November6,2006 #c