Fluent对旋转式动力机械的分析

©FluentInc.8/7/20191FluentSoftwareTrainingUGM2001IntroductiontoRotatingMachineryAnalysisUsingFluentFrankKelecyFluentInc.©FluentInc.8/7/20192FluentSoftwareTrainingUGM2001AgendaIntroductionSinglemovingreferenceframe(SRF)modelMultiplemovingreferenceframe(MRF)modelMixingplanemodelSlidingmeshmodelQuestions?©FluentInc.8/7/20193FluentSoftwareTrainingUGM2001MotivationFlowsinvolvingrotatingdomainsoccurfrequentlyinengineeringExamplescompressorsandturbinesfansandpumpsrotatingcavities,seals,andbearingsmixingequipmentfluidcouplingdevicesandtorqueconvertersairmotorsmarineandaircraftpropellersandmanymore…ComputationalFluidDynamics(CFD)todayplaysacentralroleinthedesignandanalysisofrotatingmachinery©FluentInc.8/7/20194FluentSoftwareTrainingUGM2001ExamplesofRotatingMachinerygasturbineengineautomotivewaterpumptubeaxialfansteamturbineHVACblowerunithydroturbine©FluentInc.8/7/20195FluentSoftwareTrainingUGM2001GoalsoftheTrainingProvideanintroductiontorotatingmachinerymodelingExaminethefourmajorclassesofrotatingmachineryproblemsSinglerotatingreferenceframe(SRF)Multiplerotatingreferenceframe(MRF)MixingplaneSlidingmeshPresentdetailsonmodelingrotatingmachineryproblemsusingFluentModelsetupSolutionprocess(steady-stateandunsteady)Answeryourquestions!©FluentInc.8/7/20196FluentSoftwareTrainingUGM2001TypesofRotatingMachineryInthiscourse,wewillclassifyrotatingmachineryasfollows:Turbomachinery-machineswhichaddworktoorextractworkfromafluidcompressors,fans,pumps-addworktoachieveapressureriseinthefluidturbines,windmills-extractworkfromfluidtodriveothermachinesMixingequipment-machineswhicharedesignedtomixfluid(andpossiblysolid)materialsforuseinachemicalprocessingapplicationindustrialmixingtanksRotatingtanks,seals,cavities,andotherdevicesdiskcavitiesandlabyrinthsealsingasturbineengineselectricmotorcoolingpassagesdiskdrivesrotatingtiresonautomotivevehiclesAlloftheseapplicationsinvolverotatingsurfacesanddomains(andthusmayusearotatingreferenceframeformodeling)©FluentInc.8/7/20197FluentSoftwareTrainingUGM2001ClassificationofTurbomachineryAxialmachinesFlowthroughthemachineis(ingeneral)alignedwiththeaxisofrotationExamples:propellers,axialfans/compressors/turbines,swirlersCentrifugalmachinesFlowthroughthemachineis(ingeneral)perpendiculartotheaxisofrotationExamples:liquidpumps,centrifugalfans/compressors,radialturbinesMixedFlowFlowthroughthemachineissomewherebetweenaxialandcentrifugalExample:mixedflowcompressor©FluentInc.8/7/20198FluentSoftwareTrainingUGM2001BasicProblemStatementWewishtosolvefortheflowthroughadomainwhichcontainsrotatingcomponentspropeller,compressor/turbineblade,radialimpeller,etc.stationaryand/orrotatingsurfacesductswalls,boresandcavities,sealteethsurfaces,etc.Rotation(s)assumedtobesteadyacceleratingreferenceframescanbemodeledwithsourceterms(notconsideredhere)Well-posedboundaryconditionsflowrates,pressures,temperatures,otherscalarsatinlet/outletboundarieswallmotion,thermal,otherBCsatwallsOtherconsiderations…laminar/turbulentflow,otherphysics(e.g.multiphaseflow,heattransfer)levelofinteractionbetweenmoving/stationarycomponents©FluentInc.8/7/20199FluentSoftwareTrainingUGM2001ModelingApproachesSingleRotatingFrame(SRF)EntirecomputationaldomainisreferredtorotatingreferenceframeMultipleRotatingFrame(MRF)SelectedregionsofthedomainarereferredtorotatingreferenceframesIgnoreinteractioneffectssteady-stateMixingPlane(MPM)Influenceofneighboringregionsaccountedforthroughuseofamixingplanemodelatrotating/stationarydomaininterfacesIgnorecircumferentialnon-uniformitiesintheflowsteady-stateSlidingMesh(SMM)MotionofspecificregionsaccountedforbymeshmotionalgorithmFlowvariablesinterpolatedacrossaslidinginterfaceUnsteadyproblem-cancaptureallinteractioneffectswithcompletefidelity©FluentInc.8/7/201910FluentSoftwareTrainingUGM2001SingleReferenceFrame(SRF)Modeling©FluentInc.8/7/201911FluentSoftwareTrainingUGM2001IntroductiontotheSRFModelManyproblemswhichinvolverotatingcomponentscanbemodeledusingasinglerotatingreferenceframe.Whyusearotatingreferenceframe?FlowfieldwhichisunsteadyinthestationaryframebecomessteadyintherotatingframeSteady-stateproblemsareeasiertosolve...simplerBCslowcomputationalcosteasiertopost-processandanalyzeWewilldiscussissuesrelatedtoSRFmodelinginthissection,butmanyconcepts(e.g.solversettings,physicalmodels,etc.)willalsoapplytoMRF,mixingplane,andslidingmeshmodeling.©FluentInc.8/7/201912FluentSoftwareTrainingUGM2001IllustrationofSRFmodelbladehubdomainrotatingreferenceframeaxisshroud/casing©FluentInc.8/7/201913FluentSoftwareTrainingUGM2001ImplicationsofSRFSinglefluiddomainDomainrotateswithaconstantrotationalspeedaboutaspecifiedrotationalaxisEntiredomainmoveswiththereferenceframeBoundarieswhichmovewiththefluiddomainmayassumeanyshapeBoundarieswhicharestationary(withrespecttothelaboratoryorfixedframe)mustbesurfacesofrevolutionCanemployrotationally-periodicboundariesforefficiency(reduceddomainsize)©FluentInc.8/7/201914FluentSoftwareTrainingUGM2001StationaryWallsinSRFM