fluent传热计算算例和教程

Tutorial3.PeriodicFlowandHeatTransferinaTubeBankIntroduction:Manyindustrialapplications,suchassteamgenerationinaboileroraircoolinginthecoilofanairconditioner,canbemodeledastwo-dimensionalperiodicheatow.Thistutorialillustrateshowtosetupandsolveaperiodicheattransferproblem,givenapregeneratedmesh.Thesystemthatismodeledisabankoftubescontainingaowinguidatonetemperaturethatisimmersedinaseconduidincross-owatadierenttemperature.Bothuidsarewater,andtheowisclassiedaslaminarandsteady,withaReynoldsnumberofapproximately100.Themassowrateofthecross-owisknown,andthemodelisusedtopredicttheowandtemperatureeldsthatresultfromconvectiveheattransfer.Duetosymmetryofthetubebank,andtheperiodicityoftheowinherentinthetubebankgeometry,onlyaportionofthegeometrywillbemodeledinFLUENT,withsymmetryappliedtotheouterboundaries.Theresultingmeshconsistsofaperiodicmodulewithsymmetry.Inthetutorial,theinowboundarywillberedenedasaperiodiczone,andtheoutowboundarydenedasitsshadow.Inthistutorialyouwilllearnhowto:CreateperiodiczonesDeneaspeciedperiodicmassowrateModelperiodicheattransferwithspeciedtemperaturebound-aryconditionsCalculateasolutionusingthesegregatedsolverPlottemperatureprolesonspeciedisosurfacescFluentInc.August7,19983-1PeriodicFlowandHeatTransferinaTubeBankPrerequisites:ThistutorialassumesthatyouarefamiliarwiththemenustructureinFLUENTandthatyouhavesolvedorreadTu-torial1.Somestepswillnotbeshownexplicitly.ProblemDescription:Thisproblemconsidersa2Dsectionofatubebank.AschematicoftheproblemisshowninFigure3.1.Thebankconsistsofuniformlyspacedtubeswithadiameterof1cm,thatarestaggeredinthedirectionofcross-uidow.Theircentersareseparatedbyadistanceof2cminthexdirection,and1cmintheydirection.Thebankhasadepthof1m.Becauseofthesymmetryofthetubebankgeometry,onlyaportionofthedomainneedstobemodeled.ThecomputationaldomainisshowninoutlineinFigure3.1.Amassowrateof0.05kg/sisappliedtotheinowboundaryoftheperiodicmodule.Thetem-peratureofthetubewall(Twall)is400Kandthebulktemperatureofthecross-owwater(T1)is300K.ThepropertiesofwaterthatareusedinthemodelareshowninFigure3.1.3-2cFluentInc.August7,1998PeriodicFlowandHeatTransferinaTubeBank1cmΤ∞=300K4cm0.5cmΤwall=400K{m=0.05kg/s⋅ρ=998.2kg/m3=0.001003kg/m-sμ=4182J/kg-K=0.6W/m-KcpkFigure3.1:SchematicoftheProblemPreparation1.Copythele/fluent_inc/fluent5/tut/tubebank/tubebank.mshfromtheFLUENTtutorialCDtoyourworkingdirectory.2.Startthe2DversionofFLUENT.cFluentInc.August7,19983-3PeriodicFlowandHeatTransferinaTubeBankStep1:Grid1.Readinthemeshletubebank.msh.File!Read!Case...2.Checkthegrid.Grid!CheckFLUENTwillperformvariouschecksonthemeshandwillreporttheprogressintheconsolewindow.Payparticularattentiontothereportedminimumvolume.Makesurethisisapositivenumber.3.Scalethegrid.Grid!Scale...(a)IntheUnitsConversiondrop-downlist,selectcmtocompletethephraseGridWasCreatedIncm(centimeters).(b)ClickonScaletoscalethegrid.ThenalDomainExtentsshouldappearasinthepanelabove.3-4cFluentInc.August7,1998PeriodicFlowandHeatTransferinaTubeBank4.Displaythemesh(Figure3.2).Display!Grid...GridFLUENT5.0(2d,segregated,lam)Apr13,1998Figure3.2:MeshforthePeriodicTubeBankcFluentInc.August7,19983-5PeriodicFlowandHeatTransferinaTubeBankInFigure3.2youcanseethatquadrilateralcellsareusedintheregionssurroundingthetubewalls,andtriangularcellsareusedfortherestofthedomain,resultingina\hybridmesh.Thequadri-lateralcellsprovidebetterresolutionoftheviscousgradientsnearthetubewalls.Theremainderofthecomputationaldomainiscon-venientlylledwithtriangularcells.Extra:Youcanusetherightmousebuttontocheckwhichzonenumbercorrespondstoeachboundary.Ifyouclicktherightmousebuttonononeoftheboundariesinthegraphicswindow,itszonenumber,name,andtypewillbeprintedintheFLU-ENTconsolewindow.Thisfeatureisespeciallyusefulwhenyouhaveseveralzonesofthesametypeandyouwanttodis-tinguishbetweenthemquickly.3-6cFluentInc.August7,1998PeriodicFlowandHeatTransferinaTubeBank5.Createtheperiodiczone.wall-9andwall-12,theinowandoutowboundaries,respectively,arecurrentlydenedaswallzonesandneedtoberedenedaspe-riodic.wall-9willbemadeintoatranslationallyperiodiczone,andwall-12willbedeletedandredenedaswall-9’speriodicshadow.(a)Intheconsolewindow,typethecommandsshowninboxesinthedialogbelow.Hint:YoumayneedtoenteraCRtogettheprompt.grid/modify-zones/make-periodicPeriodiczone[()]9Shadowzone[()]12Rotationalperiodic?(ifno,translational)[yes]noCreateperiodiczones?[yes]yescomputedtranslationdeltas:0.0400000.000000all26facesmatchedforzones9and12.zone12deletedcreatedperiodiczones.cFluentInc.August7,19983-7PeriodicFlowandHeatTransferinaTubeBankStep2:Models1.Keepthedefaultsolversettings.Dene!Models!Solver...2.Enableheattransferbyactivatingtheenergyequation.Dene!Models!Energy...3-8cFluentInc.August7,1998PeriodicFlowandHeatTransferinaTubeBank3.Settheperiodicowconditions.Dene!PeriodicConditions...(a)SelectSpecifyMassFlowunderType.ThiswillallowyoutospecifytheMassFlowRate.(b)EnteraMassFlowRateof0.05kg/s.(c)ClickOK.cFluentInc.August7,19983-9PeriodicFlowandHeatTransferinaTubeB