教程fluent b流动与传热

1、EnergyequationinEquationsolvedinSconductionEnergyequationinEquationsolvedinSconductionNon-conformal coupled AnisotropicMoving22017ANSYS,December28,Conduction Heat transfer isransitduetoatemperatureConduction Heat transfer isransitduetoatemperatureConductionisdirecttransfer ofheatbydirectcontact,nadj

2、acentlayersoffluidorsolidEnergyistransportedbybasicFluidsmolecules,Solidsfree32017ANSYS,December28,FouriersConductionheattransferernedbyFouriersFourierslawttheFouriersConductionheattransferernedbyFouriersFourierslawttheheattransferrateisproportionaltothegradientofkThermalqTheconstantofproportionalit

3、yisthethermal conductivity (k).kmaybeafunctionoftemperature,space,Forisotropicmaterials,kisascalarIngeneral(foranisotropicmaterials),kisaTableofkvaluesforvariousmaterialscanbefoundin the Appendix42017ANSYS,December28,EnergyequationinEquationsolvedinSconductionEnergyequationinEquationsolvedinSconduct

4、ionNon-conformal coupled AnisotropicMoving52017ANSYS,December28,EnergyEquationforSolidEquationsolvedinhEnergyEquationforSolidEquationsolvedinhk ThThedependent variablehistheTdThp062017ANSYS,December28, ingHeatTransferinRecalltherearethreeoptionsforOptioningheattransferthrough aMeshthehepre-Assignita

5、sasolidcellThisisthemostthoroughHeat canflowinallJustmeshthefluidSpecifyawallWallconductionaccountedforasdescribedinHeattransfernormal toOptionAsoption2,butenable1ormorelayersofvirtualcellswillbe如同方法2，但是激活Conduction”Heat canflowinall72017ANSYS,December28, ingHeatTransferinRecalltherearethreeoptionsf

6、orOptioningheattransferthrough aMeshthehepre-AssignitasasolidcellThisisthemostthoroughHeat canflowinallJustmeshthefluidSpecifyawallWallconductionaccountedforasdescribedinHeattransfernormal toOptionAsoption2,butenable1ormorelayersofvirtualcellswillbe如同方法2，但是激活Conduction”Heat canflowinall72017ANSYS,De

7、cember28, Toactivateconduction,selectheboundaryconditionToactivate Toactivateconduction,selectheboundaryconditionToactivateconductionforallwallswithnon-zerogrid/modify-zone/create-all-Todeactivateallconductiongrid/modify-zone/delete-all-82017ANSYS,December28, Managing Conduction FromConductionManage

8、r,sconductionboundariescanmanagedin Managing Conduction FromConductionManager,sconductionboundariescanmanagedinone ItissibletodefineboundaryconditionspanelforindividualSelectnonezone inConductionZonestoefficientlyidenticalsettingstodifferent sibletoreadandwritesettingsin.csvof slly useful for m cond

9、uctionwallsslarge92017ANSYS,December28, InFLUENT,bydefault,planarheat InFLUENT,bydefault,planarheattransferis ignored if the wall thickness is not meshed.Resultsfrommatches(1tusing3prismPlateAlongthe Flow 2017ANSYS,December28, Multi-layer Multi-layerconductionallowstosimulate Multi-layer Multi-layer

10、conductionallowstosimulatetransferthroughlayersof different Multi-layerconductionisapplicableifsolidsareo the2017ANSYS,December28,singAutomaticcreationofs naming conventionExternal singAutomaticcreationofs naming conventionExternal withEmbedded2017ANSYS,December28, EffectofThermalConductivityon Effe

11、ctofThermalConductivityonSconductionneededregardlessof2017ANSYS,December28, ConductionTheconductiono ConductionTheconductiono thermalinertiawhichcannotbeincludedviathin-wall2017ANSYS,December28, ConductionSpecificationofboundaryconditionatthewallBy ConductionSpecificationofboundaryconditionatthewall

12、Bydefault,wallisIfconductingwallAnotherconductingwallTheconnectingedgehasaAnothernon-conductingexternalwallEdgehasthesamethermal boundary condition.Heatfluxonvirtualboundariesisnotreportedthetotalheatflux2017ANSYS,December28, Conductionions oftheconduction:SSscannotbecreatedonnon-.conductioncannotbe

13、usedonmovingwallconductioncannot Conductionions oftheconduction:SSscannotbecreatedonnon-.conductioncannotbeusedonmovingwallconductioncannotbeusedwithFMGconductionisnotavailablewhenthewallissetuptoreceivethermaldataviasystemcoupling conduction is not available for 2D.conductionisavailableonlywhenther

14、e-basedsolverisconductingwallscannotbesplitormerged.Ifyouneedtosplitormergeawall,youwillneedtoturnofftheConductionoptionforthewallheWalldialogperformthesplitormergeoperation,andthenenableConduction forthenewwallsbeenadapted.Ifyouwant,besuretousethemaskTheconductioncannotbeusedonawallperformadaptionh

15、edescribedinSection29.11.1oftheFluentUserGuide.Thiswilltadaptionisperformedontheconducting2017ANSYS,December28,Non-Conformal Coupled Non-conformalcoupledAtaerfacenafluidzoneandasolidNon-Conformal Coupled Non-conformalcoupledAtaerfacenafluidzoneandasolidzone,coupledthermalwallboundarycondition isauto

16、maticallydWecanusefinemeshonfluidzoneandcoarsermeshonsolidYouso ThisrequiresmanualspecificationofCoupledheThisoptionallowsforheattransfernfluidsoneitherofthe2017ANSYS,December28, AnisotropicThermalAnisotropicthermalconductivityisonlyavailableforsolid By AnisotropicThermalAnisotropicthermalconductivi

17、tyisonlyavailableforsolid Bydefault,thethermalconductivityisconsideredtobe Foranisotropicmaterials,thethermalconductivityisa q ijThethermalconductivitymatrixcanbedefinedusingoneof five different methods:General anisotropicBiaxialAnisotropicthermalconductivity2017ANSYS,December28, AnisotropicThermalC

18、onductivityforSolidDefiningparametersmay AnisotropicThermalConductivityforSolidDefiningparametersmaydependonUDForconstant/polynomialdefinitionisalso conductionCylindrical2017ANSYS,December28, EnergyequationinEquationsolvedin EnergyequationinEquationsolvedinSconductionNon-conformal coupled Anisotropi

19、cMoving2017ANSYS,December28, ovingEquationsolvedinFLUENT(for movingsolids)h ovingEquationsolvedinFLUENT(for movingsolids)hVhk T hSolid(FouriersTheconvectivetermcomesfromandescriptionofsolidIfthemeshmoveswiththesolidlikeformeshorrigidbodydeformingmeshion),thenthesolid motion2017ANSYS,December28, ovin

20、gThevelocityfieldistakenfromtheSolid ovingThevelocityfieldistakenfromtheSolid ionandtthosevelocityfieldssatisfytheConvectioninconductingsolidsisjustifiedSolidtranslationofanextrudedgeometry(slab,plate Solidionofageometryof2017ANSYS,December28, ovingleof convectioninconductinglass ovingleof convectio

21、ninconductinglassranslationinaAsolidmeshedsheetisPrescribedAdiabaticgradientisBrakediscwithsourceThe“redwall”correspondstoanuncoupledpairofawallandits2017ANSYS,December28, ovingMovingreferenceframe(MRF) ovingMovingreferenceframe(MRF)isnotfortheentiresolidhefollowingbecausethesolidis notabodyof Brake

22、discwith5003002017ANSYS,December28, ovingCanwetreat theseproblems usingaJustlike ovingCanwetreat theseproblems usingaJustlikeforthefluidproblemthemultiplereferenceaybeausefulBrakediscwithSolidheMRF(body ofSolidSolid zone withholes).heicFrameofReference(SRF) SolidThispartmayactuallybeTheeffectofionhe

23、attransferwillbeprovidedbythemovingmaterial surrounding this zone.2017ANSYS,December28, ovingSolidsTurbomachineryWecan ovingSolidsTurbomachineryWecantreat thisproblemusingasteadyapproachtheappropriatewallboundaryconditionsare Turbomachinery Solid Wall/ Wallonsolid Wall/ShadowonfluidSThermallySionary

24、 wall Movingwall(relativeadjacentcell2017ANSYS,December28, ovingUnsteadyMovingreferenceframeproblemswiththesameso ovingUnsteadyMovingreferenceframeproblemswiththesamesobeusedinions asinsteadySlidingmeshorrigidbodydeformingmeshisawayoftreatingtheunsteadyhouldbelocatedntwofluid2017ANSYS,December28, ov

25、ingMovingreferenceframe(MRF)approachisvalidforlcases. 运动参考系(MRF)Rigid-body ovingMovingreferenceframe(MRF)approachisvalidforlcases. 运动参考系(MRF)Rigid-bodytranslationofan(slab,plate,sheet,Rigid-body ionofasolidofrevolution MultiplereferenceMovingsolidcanbetreatedasionaryifthefluidorsolidhesameframeof的Sl

26、idingmesh isoftenthemostaccurate2017ANSYS,December28, EnergyequationinEquationsolvedin EnergyequationinEquationsolvedinSconductionNon-conformal coupled AnisotropicMoving2017ANSYS,December28, Convergencearametersaffectingsolution Convergencearametersaffectingsolution Single-/double-Explicitrelaxation

27、oftheenergyImportanceofsecondarygradients MultiGrid methods2017ANSYS,December28, Convergence Convergencedifficultiescanberecognizedbyfollowing Convergence ConvergencedifficultiescanberecognizedbyfollowingOverallimbalanceinheatfluxatSlowconvergencerate(severalthousandtLocal(cell)temperaturesreachingn

28、onphysicalSkewedcellsandedconditionssocauseconvergenceTheseproblemscanbeeithermitigatedorythroughsimplemodificationstosolution2017ANSYS,December28, Double-Thedouble-solverisdesignedtotruncationerrorandthusimprovetheoverallheat uet2 As ageneralrule,thedoublesolver Double-Thedouble-solverisdesignedtot

29、runcationerrorandthusimprovetheoverallheat uet2 As ageneralrule,thedoublesolvershouldenabledunderthefollowingCaseswithlargeheatfluxes(orderof问题中包含大的热通量（MW量级heenergyWidelyvaryingsolidproperties(functionsoftemperature)suchasnonlinear Caseswheretherearelargehermalconductivityestiff. emoredifficulttoain

30、at.2017ANSYS,December28, Explicit Under-Wecanwriteagenericfinitevolumemethodofa Explicit Under-WecanwriteagenericfinitevolumemethodofatransportsbeendiscretizedusingWhere is the independent variable, a is the contribution of the variable to diffusive and advective fluxes through the cell fa,thesubscr

31、iptpdenotesvaluesofandainacellandthe subscript nb denotes the values of and a in all the neighboring cellsFortheenergyequationistheBydefaultFluentusesimplicitunder-relaxationfortheenergySometimesiftheenergyequationisnotconverging,itcanhelptounder-relaxthentheequation,whichisknownasexplicitunder-2017

32、ANSYS,December28, Explicit Under-dtoactivateexplicitunder-relaxationtemperature(enterasyouwouldany(rpsetvar Explicit Under-dtoactivateexplicitunder-relaxationtemperature(enterasyouwouldany(rpsetvar temperature/explicit-relax? ImprovedconvergenceforpoorqualityImprovedconvergencewhenmaterialpropertiesarestronglydependent on temperatureEnergyunder-relaxationfactorof1OncethedTemperatureURFtypically0.20.5andenergyURF=TheenergyURFisforthe2017ANSYS,December28, SecondaryWhatis a secondarySecondary SecondaryWhatis a secondarySecondarygradientsareusedprimarilyasameasure(thefluxvecto