fluent中多孔介质设置问题和算例Word文档格式.docx
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圆锥坐标与球坐标请参考fluent帮助。
2）定义粘性阻力1/a与内部阻力C2：
请参看本人上一篇博文“终于搞清fluent中多孔粘性阻力与内部阻力的计算方法”，此处不赘述；
3）如果了定义粘性阻力1/a与内部阻力C2,就不用定义C1与C0，因为这是两种不同的定义方法，C1与C0只在幂率模型中出现，该处保持默认就行了；
4）定义孔隙率porousity，默认值1表示全开放，此值按实验测值填写即可。
完了，其他设置与普通k-e或RSM相同。
总结一下，与君共享!
Tutorial7.ModelingFlowThroughPorousMedia
Introduction
Manyindustrialapplicationsinvolvethemodelingofflowthroughporousmedia,suchasfilters,catalystbeds,andpacking.Thistutorialillustrateshowtosetupandsolveaprobleminvolvinggasflowthroughporousmedia.
Theindustrialproblemsolvedhereinvolvesgasflowthroughacatalyticconverter.Catalyticconvertersarecommonlyusedtopurifyemissionsfromgasolineanddieselenginesbyconvertingenvironmentallyhazardousexhaustemissionstoacceptablesubstances.
Examplesofsuchemissionsincludecarbonmonoxide（CO）,nitrogenoxides（NOx）,andunburnedhydrocarbonfuels.Theseexhaustgasemissionsareforcedthroughasubstrate,whichisaceramicstructurecoatedwithametalcatalystsuchasplatinumorpalladium.
Thenatureoftheexhaustgasflowisaveryimportantfactorindeterminingtheperformanceofthecatalyticconverter.Ofparticularimportanceisthepressuregradientandvelocitydistributionthroughthesubstrate.HenceCFDanalysisisusedtodesignefficientcatalyticconverters:
bymodelingtheexhaustgasflow,thepressuredropandtheuniformityofflowthroughthesubstratecanbedetermined.Inthistutorial,FLUENTisusedtomodeltheflowofnitrogengasthroughacatalyticconvertergeometry,sothattheflowfieldstructuremaybeanalyzed.
Thistutorialdemonstrateshowtodothefollowing:
_Setupaporouszoneforthesubstratewithappropriateresistances.
_Calculateasolutionforgasflowthroughthecatalyticconverterusingthepressurebasedsolver.
_Plotpressureandvelocitydistributiononspecifiedplanesofthegeometry.
_Determinethepressuredropthroughthesubstrateandthedegreeofnon-uniformityofflowthroughcrosssectionsofthegeometryusingX-Yplotsandnumericalreports.
ProblemDescription
ThecatalyticconvertermodeledhereisshowninFigure7.1.Thenitrogenflowsinthroughtheinletwithauniformvelocityof22.6m/s,passesthroughaceramicmonolithsubstratewithsquareshapedchannels,andthenexitsthroughtheoutlet.
Whiletheflowintheinletandoutletsectionsisturbulent,theflowthroughthesubstrateislaminarandischaracterizedbyinertialandviscouslosscoefficientsintheflow（X）direction.Thesubstrateisimpermeableinotherdirections,whichismodeledusinglosscoefficientswhosevaluesarethreeordersofmagnitudehigherthanintheXdirection.
SetupandSolution
Step1:
Grid
1.Readthemeshfile（catalyticconverter.msh）.
File/Read/Case...
2.Checkthegrid.Grid/Check
FLUENTwillperformvariouschecksonthemeshandreporttheprogressintheconsole.Makesurethattheminimumvolumereportedisapositivenumber.
3.Scalethegrid.
Grid!
Scale...
（a）SelectmmfromtheGridWasCreatedIndrop-downlist.
（b）ClicktheChangeLengthUnitsbutton.Alldimensionswillnowbeshowninmillimeters.
（c）ClickScaleandclosetheScaleGridpanel.
4.Displaythemesh.Display/Grid...
（a）Makesurethatinlet,outlet,substrate-wall,andwallareselectedintheSurfacesselectionlist.
（b）ClickDisplay.
（c）RotatetheviewandzoomintogetthedisplayshowninFigure7.2.
（d）ClosetheGridDisplaypanel.
Thehexmeshonthegeometrycontainsatotalof34,580cells.
Step2:
Models
1.Retainthedefaultsolversettings.Define/Models/Solver...
2.Selectthestandardk-εturbulencemodel.Define/Models/Viscous...
Step3:
Materials
1.AddnitrogentothelistoffluidmaterialsbycopyingitfromtheFluentDatabaseformaterials.Define/Materials...
（a）ClicktheFluentDatabase...buttontoopentheFluentDatabaseMaterialspanel.
i.Selectnitrogen（n2）fromthelistofFluentFluidMaterials.
ii.ClickCopytocopytheinformationfornitrogentoyourlistoffluidmaterials.
iii.ClosetheFluentDatabaseMaterialspanel.
（b）ClosetheMaterialspanel.
Step4:
BoundaryConditions.Define/BoundaryConditions...
1.Settheboundaryconditionsforthefluid（fluid）.
（a）SelectnitrogenfromtheMaterialNamedrop-downlist.
（b）ClickOKtoclosetheFluidpanel.
2.Settheboundaryconditionsforthesubstrate（substrate）.
（b）EnablethePorousZoneoptiontoactivatetheporouszonemodel.
（c）EnabletheLaminarZoneoptiontosolvetheflowintheporouszonewithoutturbulence.
（d）ClickthePorousZonetab.
i.MakesurethattheprincipaldirectionvectorsaresetasshowninTable7.1.Usethescrollbartoaccessthefieldsthatarenotinitiallyvisibleinthepanel.
ii.EnterthevaluesinTable7.2fortheViscousResistanceandInertialResistance.Scrolldowntoaccessthefieldsthatarenotinitiallyvisibleinthepanel.
（e）ClickOKtoclosetheFluidpanel.
3.Setthevelocityandturbulenceboundaryconditionsattheinlet（inlet）.
（a）Enter22.6m/sfortheVelocityMagnitude.
（b）SelectIntensityandHydraulicDiameterfromtheSpecificationMethoddropdownlistintheTurbulencegroupbox.
（c）Retainthedefaultvalueof10%fortheTurbulentIntensity.
（d）Enter42mmfortheHydraulicDiameter.
（e）ClickOKtoclosetheVelocityInletpanel.
4.Settheboundaryconditionsattheoutlet（outlet）.
（a）Retainthedefaultsettingof0forGaugePressure.
（c）Enter5%fortheBackflowTurbulentIntensity.
（d）Enter42mmfortheBackflowHydraulicDiameter.
（e）ClickOKtoclosethePressureOutletpanel.
5.Retainthedefaultboundaryconditionsforthewalls（substrate-wallandwall）andclosetheBoundaryConditionspanel.
Step5:
Solution
1.Setthesolutionparameters.Solve/Controls/Solution...
（a）RetainthedefaultsettingsforUnder-RelaxationFactors.
（b）SelectSecondOrderUpwindfromtheMomentumdrop-downlistintheDiscretizationgroupbox.
（c）ClickOKtoclosetheSolutionControlspanel.
2.Enabletheplottingofresidualsduringthecalculation.Solve/Monitors/Residual...
（a）EnablePlotintheOptionsgroupbox.
（b）ClickOKtoclosetheResidualMonitorspanel.
3.Enabletheplottingofthemassflowrateattheoutlet.
Solve/Monitors/Surface...
（a）SettheSurfaceMonitorsto1.
（b）EnablethePlotandWriteoptionsformonitor-1,andclicktheDefine...buttontoopentheDefineSurfaceMonitorpanel.
i.SelectMassFlowRatefromtheReportTypedrop-downlist.
ii.SelectoutletfromtheSurfacesselectionlist.
iii.ClickOKtoclosetheDefineSurfaceMonitorspanel.
（c）ClickOKtoclosetheSurfaceMonitorspanel.
4.Initializethesolutionfromtheinlet.Solve/Initialize/Initialize...
（a）SelectinletfromtheComputeFromdrop-downlist.
（b）ClickInitandclosetheSolutionInitializationpanel.
5.Savethecasefile（catalyticconverter.cas）.File/Write/Case...
6.Runthecalculationbyrequesting100iterations.Solve/Iterate...
（a）Enter100fortheNumberofIterations.
（b）ClickIterate.
TheFLUENTcalculationwillconvergeinapproximately70iterations.Bythispointthemassflowratemonitorhasattendedout,asseeninFigure7.3.
（c）ClosetheIteratepanel.
7.Savethecaseanddatafiles（catalyticconverter.casandcatalyticconverter.dat）.
File/Write/Case&
Data...
Note:
Ifyouchooseafilenamethatalreadyexistsinthecurrentfolder,FLUENT
willpromptyouforconfirmationtooverwritethefile.
Step6:
Post-processing
1.Createasurfacepassingthroughthecenterlineforpost-processingpurposes.
Surface/Iso-Surface...
（a）SelectGrid...andY-CoordinatefromtheSurfaceofConstantdrop-downlists.
（b）ClickComputetocalculatetheMinandMaxvalues.
（c）Retainthedefaultvalueof0fortheIso-Values.
（d）Entery=0fortheNewSurfaceName.
（e）ClickCreate.
2.Createcross-sectionalsurfacesatlocationsoneithersideofthesubstrate,aswellasatitscenter.
Surface/Iso-Surface...
（a）SelectGrid...andX-CoordinatefromtheSurfaceofConstantdrop-downlists.
（c）Enter95forIso-Values.
（d）Enterx=95fortheNewSurfaceName.
（f）Inasimilarmanner,createsurfacesnamedx=130andx=165withIso-Valuesof130and165,respectively.ClosetheIso-Surfacepanelafterallthesurfaceshavebeencreated.
3.Createalinesurfaceforthecenterlineoftheporousmedia.
Surface/Line/Rake...
（a）EnterthecoordinatesofthelineunderEndPoints,usingthestartingcoordinateof（95,0,0）andanendingcoordinateof（165,0,0）,asshown.
（b）Enterporous-clfortheNewSurfaceName.
（c）ClickCreatetocreatethesurface.
（d）ClosetheLine/RakeSurfacepanel.
4.Displaythetwowallzones（substrate-wallandwall）.Display/Grid...
（a）DisabletheEdgesoption.
（b）EnabletheFacesoption.
（c）DeselectinletandoutletinthelistunderSurfaces,andmakesurethatonlysubstrate-wallandwallareselected.
（d）C
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