FLUENT流化床模拟实例

Tutorial:UsingtheEulerianMultiphaseModelwithSpeciesTransportIntroductionFluidizedbedsareusedinprocesseswheregas/solidmasstransferisofimportance.Thede-compositionofozone(O3),usingparticlesasacatalyst,createsasuitablelow-temperatureenvironmentformasstransfer.Thistutorialsolvesagas/solidowwithasimpleone-stepozonedecompositionreactioninauidizedbed.ThereactionequationisO3!1:5O2(1)Thistutorialdemonstrateshowtodothefollowing:UsethegranularEulerianmultiphasemodelwithspeciestransport.Denetherateofreactionwithauser-denedfunction(UDF).DenetheSyamlal-O'Briendragcorrelationwithauser-denedfunction(UDF)usingappropriateparameters.Setboundaryconditionsforinternalow.Denetheuidandsolidphases.Calculateasolutionusing2Dplanargeometryinconjunctionwiththepressure-basedsolver.Solveatime-accuratetransientproblemwithdatasamplingfortimestatistics.PrerequisitesThistutorialassumesthatyouarefamiliarwiththeFLUENTinterfaceandthatyouhaveagoodunderstandingofbasicsetupandsolutionprocedures.Somestepswillnotbeshownexplicitly.InthistutorialyouwillusetheEulerianmultiphasemodelwithspeciestransport.Ifyouhavenotusedthisfeaturebefore,refertotheFLUENT6.3User'sGuide.cFluentInc.October30,20061UsingtheEulerianMultiphaseModelwithSpeciesTransportProblemDescriptionTheprobleminvolvesthetransientstartupofozonedecompositioninauidizedbed.Theuidphaseisamixtureofozoneandair,whilethesolidphaseconsistsofsandparticleswithan87.75microndiameter.AschematicoftheuidizedbedisshowninFigure1.Thedomainismodeledasa2Dplanarcylindricalcase.volumefraction0.52ofsolidspressureoutletuniformvelocityinletu=0.08m/s0PagaugeFigure1:ProblemSpecication2cFluentInc.October30,2006UsingtheEulerianMultiphaseModelwithSpeciesTransportPreparation1.Copytheles2-D-FBedOzone.msh.gz,rrate.c,andbpdrag.ctoyourworkingfolder.2.Startthe2Ddouble-precision(2ddp)versionofFLUENT.SetupandSolutionStep1:Grid1.Readthegridle(2-D-FBed_Ozone.msh).File!Read!Case...AsFLUENTreadsthegridle,itwillreportitsprogressintheconsole.2.Checkthegrid.Grid!CheckFLUENTwillperformvariouschecksonthemeshandwillreporttheprogressintheconsole.Makesuretheminimumvolumereportedisapositivenumber.3.Displaythegridusingthedefaultsettings.Display!Grid...GridFLUENT6.3(2d,dp,pbns,lam)Figure2:GridDisplay4.Rotatetheviewsothattheinletoftheuidizedbedisatthebottom.Display!Views...cFluentInc.October30,20063UsingtheEulerianMultiphaseModelwithSpeciesTransport(a)ClicktheCamera...buttontoopentheCameraParameterspanel.i.Dragtheindicatorofthedialwiththeleftmousebuttoninthecounter-clockwisedirectionuntiltheuprightview(-90)isdisplayed(Figure2).ii.ClosetheCameraParameterspanel.(b)ClicktheSavebuttonintheActionsgroupboxintheViewspaneltosavetheuprightview.Whenyoudothis,view-0willbeaddedtothelistofViews.(c)ClosetheViewspanel.Youcanusetheprobemousebuttontocheckwhichzonenumbercorrespondstoeachboundary.Ifyouclicktheprobemousebuttonononeoftheboundariesinthegraphicswindow,itszonenumber,name,andtypewillbeprintedintheFLUENTconsole.Thisfeatureisespeciallyusefulwhenyouhaveseveralzonesofthesametypeandyouwanttodistinguishbetweenthemquickly.4cFluentInc.October30,2006UsingtheEulerianMultiphaseModelwithSpeciesTransportStep2:Models1.Specifyatransient,2Dmodel.Dene!Models!Solver...(a)RetainthedefaultselectionofPressureBasedfromtheSolverlistand2DfromtheSpacelist.Thepressurebasedsolvermustbeusedformultiphasecalculations.(b)SelectUnsteadyfromtheTimelist.(c)ClickOKtoclosetheSolverpanel.2.Denethemultiphasemodel.Dene!Models!Multiphase...(a)SelectEulerianfromtheModellist.ThepanelwillexpandtoshowtheinputsfortheEulerianmodel.cFluentInc.October30,20065UsingtheEulerianMultiphaseModelwithSpeciesTransport(b)Retainthedefaultvalueof2forNumberofPhases.(c)ClickOKtoclosetheMultiphaseModelpanel.3.Denethespeciesmodel.Dene!Models!Species!Transport&Reaction...(a)SelectSpeciesTransportfromtheModellist.TheSpeciesModelpanelwillexpand.(b)EnableVolumetricfromtheReactionsgroupbox.(c)DisableDiusionEnergySourcefromtheOptionsgroupbox.(d)ClickOKtoclosetheSpeciesModelpanel.6cFluentInc.October30,2006UsingtheEulerianMultiphaseModelwithSpeciesTransportFLUENTwilllistthepropertiesrequiredforthemodelsthatyouenabled,intheconsole.AnInformationdialogboxwillappear,remindingyoutoconrmthepropertyvaluesthathavebeenextractedfromthedatabase.(e)ClickOKintheInformationdialogboxtocontinue.Step3:MaterialsDene!Materials...1.Createanewmaterialcalledair+ozone.(a)ClicktheFluentDatabase...buttontoopentheFluentDatabaseMaterialspanel.i.SelectuidfromtheMaterialTypedrop-downlist.ii.Selectozone(o3)fromtheFluentFluidMaterialsselectionlist.iii.ClickCopytocopytheinformationforozonetoyourmodelandclosetheFluentDatabaseMaterialspanel.(b)SelectmixturefromtheMaterialTypedrop-downlist.(c)Enterair+ozoneforName.(d)ClickChange/Create.WhenyouclickChange/Create,aQuestiondialogboxwillappear,askingyouifmixture-templateshouldbeoverwritten.ClickNotoretainmixture-templateandaddthenewmaterial,air+ozone,tothelist.TheMaterialspanelwillbeupdatedtoshowthenewmaterialnameintheFluentMixtureMaterialslist.cFluentInc.October30,20067Usingt