电子器件 技术文件COMSOL-Heat-Transfer-44

HeatTransfer,GeneralIntroduction,

V4.4HeattransferphenomenaConductionHeattransferbytranslationofsolidsConvectioninfluidsRadiationBioheatingMultiphysicscouplingsJouleHeatingConjugateHeatTransferPhaseChangeInductiveHeatingThermalExpansionCOMSOLVersion4.4ProductSuiteHeatTransfer

MODELINGcapabilities

HeattransferinsolidsIsotropicoranisotropic,linearornonlinearmaterialsHeattransferinthinshellsThinthermallyresistivelayersSinglelayerMultiplelayersstructureHeattransferbytranslationofsolidsHeatsource,userdefinedorfromotherphysicsTemperatureofadiscbrakeofacarinbrake-and-releasesequenceHeattransferinfluidsLaminarandturbulentflowsk-emodelk-wmodel*SSTmodel*LowReynolds,k-emodelSpalart-Allmarasmodel*ViscousheatingPressureworkFluid/solidinterfacewithtemperaturecontinuitywithboundarylayerapproximationDedicatedboundaryconditionsInflowheatflux,OutflowOpenboundaryScreen,fan*RequirestheCFDmoduleHeatTransferinterfacelistinCOMSOLMultiphysicsHeattransferinfluidsConjugateheattransferNaturalconvection(freeconvection)ForcedconvectionLaminarandturbulentflowregimesTemperatureboundarylayerfor

turbulencemodelsPredefinedlibraryofheattransfercoefficientsbasedonNusseltcorrelationsFanandscreenboundaryconditionTemperatureprofileinapowersupplyunit.Anextractingfanandaperforatedgrillecauseanairflowintheenclosuretocoolinternaldevices.PipeflowHeattransferinpipesConductionandadvection(convection)Non-isothermalflowinpipesAutomatictransitionbetweenlaminarandturbulentflowBidirectionalcouplingsbetween

pipesand2Dor3DdomainsPipepropertiesCross-sectionsSurfaceroughnessCoolingofasteeringwheelplasticmoldincludingpipeflowandheattransferincoolingchannels.HeattransferwithphasechangeTheHeatTransferwithPhaseChangeusingapparentheatcapacityformulationMaterialpropertiesforeachphasePhasechangetemperatureLatentheatMaterialpropertiessmoothingduringphasechangePhasechangemodelingforcontinuouscastingofametalrodfrommeltedtosolidstate.HeattransferinporousmediaCouplingbetweenfluidandsolidmatrixpartsGeothermalheatingImmobilefluidsThermaldispersionduetotortuous

pathsinpoursmediaVolumeaveragingofmaterialpropertiesVelocityfield(left)andtemperature(right)profileduetobuoyancyinporousmediaHeattransferinbiologicaltissuesHeattransferinlivingtissueTissueandbloodpropertiesBloodperfusionrateArterialbloodtemperatureMetabolicheatrateBioheatsourceDamageinlivingtissuesTemperaturethresholdmodelEnergyabsorptionmodelExternalheatsources(RF,DCcurrent)Tissuenecrosisareaduringtumorablationprocessat100s(top)and300s(bottom).Surface-to-surfaceradiationCalculationofgreybody

radiationviewfactorswithshadowingeffectsWavelengthdependentpropertiesDiffusereflectionTemperature-dependentemissivityExternalradiationsourcesUserdefinedFromthesun(automaticpositioncomputation)TemperaturedistributioninalightbulbgeneratedbytheradiatingfilamentRadiationinparticipatingmediaEmission/absorptionin

participatingmediaRayscatteringIsotropic,Linearanisotropic,NonlinearAnisotropicScatteringRadiationdiscretizationmethodsRosselandapproximationP1approximationDiscreteOrdinateMethodRadiativeheattransferinautilityboilerwithinternalobstaclesThermoelectriceffectMultiphysicscouplingbetween HeattransferinterfacesandElectriccurrentsinterfacesCombinesJoule,Peltier,Seebeck,Thomsoneffects.TemperaturedropdemonstratingPeltiereffectinathermoelectricleg.ThermalcontactPredefinedmodelsforpressuredependantthermalconductance(constrictionconductance)conductancethroughthefluid(gapconductance)surface-to-surfaceradiationcontribution(radiativeconductance)CouplingwithstructuralmechanicscontactandelectricalcontactFrictionheatsourcewithpartitioncoefficientdefinitionTemperatureintwocontactingpartsofaswitchinductedbyJouleheating.Electricalcurrentandtheheatflowfromoneparttotheotherthroughthecontactsurface.Thermalandelectricalapparentresistancesarecoupledtothemechanicalcontactpressure.AdditionalfeaturesoverviewGeometry,assemblyHeatcontinuityacrosspairsThermallyResistiveLayersbetweenpairsidesPeriodicityInfiniteelementsPredefinedpropertiesforliquidsandgasesincludingtemperatureandpressuredependencyArbitraryuserdefinedpropertiesTwoaluminumplates,modeledasinfinitelylong,arejoinedbygeneratingfrictionheatwitharotatingtool.Completefeatureslistavailableonsol.fr/products/specifications/heat-transfer/

HeatTransferExamples

AvailableintheModelLibraryortheModelGallery

moreon/showroom/product/ht/Thisfigureshowsthetemperatureprofileandthestreamlinesinashellandtubeheatexchanger.Twoseparatedfluidsatdifferenttemperaturesflowthroughtheheatexchanger,onethroughthetubes(tubeside,redstreamlines)andtheotherthroughtheshellaroundthetubes(shellside,bluestreamlines).HeatexchangerVentilationThemodelinvestigatestheperformanceofadisplacementventilationsystem.TheflowismodeledusingtheNon-IsothermalTurbulentFlow,k-omegaModelinterface.Thisfigureshowstheisotherms

inaroom.ElectroniccoolingThemodelexaminestheaircoolingofapowersupplyunit(PSU)withmultipleelectronicscomponentsactingasheatsources.Finsareusedtoimprovecoolingefficiency.Toachievehighaccuracy,thesimulationaccountsforheattransportincombinationwithfluidflow.Thisfigureshowsanhorizontalboardwithforcedconvection(fancooling).FurnacereactorThismodelshowsafurnacereactordesignthatheatsasusceptorofgraphite,usingan8kWRFsignalat20kHz.Thetemperaturedistributionoverthewaferisextracted,aswellasthetemperatureontheouterQuartztube.Atthesehightemperature(~2000oC)theheatfluxisdominatedbyradiation.

Thedesignofthechamberiscrucialtoreachauniformtemperature,efficientheating,andcontrolofhightemperatureregions.HeatlossesinwiresTemperatureraiseinacablewithPoE/PoE+technology.Inthismodel,theheatsourceisduetotheJouleheatingeffect.

This,developedbyNexans,takesintoconsiderationseveralconfigurationsofcablebundlesinordertooptimizetemperaturedistribution.FiniteElementAnalysisofCablesHeatingDuetoPoE/PoE+S.Francois1,andP.Namy2

1NexansResearchCenter,Lyoncedex,France

2SIMTEC,Grenoble,FrancePresentedatCOMSOLConference2010ParisFrictionstirweldingInthismodel,twoaluminumplatesarejoinedbygeneratingfrictionheatwitharotatingtool.Heatistransferredbyconductionfromthetoolintotheplates.Themovementofthetoolistakenintoaccountbyaddingtranslationasanadvectiveterm.Theplatesurfacesarecooledthroughfreeconvectionandsurface-to-ambientradiation.ThermalstressThismodelsaccountsforheattransportandstructuralstressesandstrainsresultingfromhightemperaturegradientsinastatorblade.

ItcouplestheHeatTransferinSolidsandSolidMechanicsinterfaces.ThisplotshowsthevonMisesstressandthedeformedshapeoftheblade.TinmeltingfrontPhasetransitioninacavitycontainingbothsolidandliquidtinissubmittedtoatemperaturedifferencebetweenleftandrightboundaries.Fluidandsolidpartsaresolvedinseparatedomainssharingamovingmeltingfront.ThepositionofthisboundarythroughtimeiscalculatedaccordingtotheStefanenergybalancecondition.Inthemelt,motiongeneratedbynaturalconvectionisexpectedduetothetemperaturegradient.Thismotion,inturn,influencesthefrontdisplacement.LightbulbThismodeltreatsthefreeconvectionofargongaswithinalightbulb.Itshowsthecouplingofheattransport(conduction,radiation,andadvection)tomomentumtransport(non-isothermalflow)inducedbydensityvariationscausedbytemperature(freeconvection).SolarandambiantradiationThismodelusestheexternalradiativeheatsourcefeaturewithsolarpositionoption.Thesun'spositionandshadoweffectsareautomaticallyupdatedduringthesimulation.ThewavelengthdependencyofsurfaceemissivityisconsideredPowertransistorThismodelsimulatesasystemconsistingofasmallpartofacircuitboardcontainingapowertransistorandthecopperpathwaysconnectedtothetransistor.Thesimulationestimatestheoperatingtemperatureofthetransistor.Weinvestigateifheatsinkmountingisnecessaryoriftheoperatingtemperaturecanbelowenoughintheabsenceofaheatsink.FluidflowwithJouleheatingThismodelesti