CFX13_03_计算域及边界条件设置.ppt

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1、Chapter3计算域及边界条件的设置CFX条件设置DomainsDomainsareregionsofspaceinwhichtheequationsoffluidfloworheattransferaresolvedOnlythemeshcomponentswhichareincludedinadomainareincludedinthesimulatione.g.Asimulationofacopperheatingcoilinwaterwillrequireafluiddomainandasoliddomain.e.g.

2、Toaccountforrotationalmotion,therotorisplacedinarotatingdomain.RotorStatorHowtoCreateaDomain(asshownearlier)DefineDomainPropertiesRight-clickonthedomainandpickEditOrright-clickonFlowAnalysis1toinsertanewdomainWheneditinganitemanewtabpanelopenscontainingtheproperties.

3、Youcanswitchbetweenopentabs.Sub-tabscontainvariousdifferentpropertiesCompletetherequiredfieldsoneachsub-tabtodefinethedomainOptionalfieldsareactivatedbyenablingacheckboxDomainCreationGeneralOptionspanel:BasicSettingsLocation:Onlyassembliesand3DprimitivesDomainType:Fl

4、uid,Solid,orPorousCoordinateFrame:selectcoordinateframefromwhichalldomaininputswillbereferencedtoNottobeconfusedwiththereferenceframe,whichcanbestationaryorrotatingThedefaultCoord0frameisusuallyusedFluidsandParticlesDefinitions:selecttheparticipatingmaterialsEx.2:Pre

5、ference=100,000PaDomainCreation–ReferencePressureGeneralOptionspanel:DomainModelsReferencePressureRepresentstheabsolutepressuredatumfromwhichallrelativepressuresaremeasuredPabs=Preference+PrelativePressuresspecifiedatboundaryandinitialconditionsarerelativetotheRefere

6、ncePressureUsedtoavoidproblemswithround-offerrorswhichoccurwhenthelocalpressuredifferencesinafluidaresmallcomparedtotheabsolutepressurelevelPressurePressureEx.1:Preference=0PaPrefPrel,max=100,001PaPrel,min=99,999PaPrel,max=1PaPrel,min=-1PaPrefDomainCreation-BuoyancyG

7、eneralOptionspanel:BuoyancyWhengravityactsonfluidregionswithdifferentdensitiesabuoyancyforcearisesWhenbuoyancyisincluded,asourcetermisaddedtothemomentumequationsbasedonthedifferencebetweenthefluiddensityandareferencedensitySM,buoy=(ρ–ρref)gρrefisthereferencedensity.T

8、hisisjustthedatumfromwhichalldensitiesareevaluated.Fluidwithdensityotherthanρrefwillhaveeitherapositiveornegativebuoyancyforceappli