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1、SolvedwithCOMSOLMultiphysics4.2ElectricalHeatinginaBusbarIntroductionThemodelthatyoucreateanalyzesabusbardesignedtoconductadirectcurrentfromatransformertoanelectricaldevice;seeFigure1.Thecurrentconductedinthebusbarproducesheatduetotheresistivelosses,aphenomen
2、onreferredtoasJouleheating.TheJouleheatingeffectisdescribedbyconservationlawsforelectriccurrentandenergy.Oncesolvedfor,thetwoconservationlawsgivethetemperatureandelectricfield,respectively.Figure1:Photoofabusbarinstallation,andthegeometryofthebusbarusedinthis
3、model.Thegoalofyoursimulationistopreciselycalculatehowmuchthebusbarheatsupandtostudytheinfluenceofadesignparameter,thewidthofthedevice,onthephenomenon.ModelDefinitionThebusbarismadeofcopperwhiletheboltsaremadeoftitanium.Thischoiceofmaterialsisimportantsinceti
4、taniumhasalowerelectricalconductivitythancopperandissubjectedtoahighercurrentdensity.Allsurfaces,excepttheboltcontactsurfaces,arecooledbynaturalconvectionintheairsurroundingthebusbar.Youcanassumethattheboltcross-sectionboundariesdonotcontributetocoolingorheat
5、ingofthedevice.Theelectricpotentialatthe©2011COMSOL1
6、ELECTRICALHEATINGINABUSBARSolvedwithCOMSOLMultiphysics4.2upper-rightverticalboltsurfaceis20mV,andthatthepotentialatthetwohorizontalsurfacesofthelowerboltsis0V.CopperAllotherboundaries:naturalconvectionTitan
7、iumGroundElectricpotential:20mVFigure2:Materialandboundarysettingsinthemodel.ResultsandDiscussionTheplotshowninFigure3displaysthetemperatureinthebusbar,whichissubstantiallyhigherthantheambienttemperature293K.Thetemperaturedifferenceinthedeviceislessthan10K,du
8、etothehighthermalconductivityofcopperandtitanium.Thetemperaturevariationsarelargestonthetopbolt,whichconductsdoubletheamountofcurrentcomparedtothetwolowerones.Figure3:Temperaturedistributioninthebusbar.2
9、ELECTRICALHEATINGINABUSBAR©2011COMSOLSolvedwithCOMSOLMu
10、ltiphysics4.2ThecolorrangeoftheplotinFigure4betterillustratesthelowtemperaturevariationinthecopperpartofthedevice.Thetemperaturedistributionissymmetricwithaverticalmirrorplanerunningbetwe
