【文档说明】医学课件离心泵CFX流场分析教程.ppt，共(22)页，2.113 MB，由小橙橙上传

转载请保留链接：https://www.ichengzhen.cn/view-256287.html

以下为本文档部分文字说明：

ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.WorkshopSupplementWS5:CavitatingCentrifugalPumpWS5-1April28,2009Inventory#002599I

ntroductionThePurposeofthetutorialistomodelcavitationinacentrifugalpump,whichinvolvestheuseofarotationdomainandthecavitationmodel.Theproblemconsistso

fafivebladecentrifugalpumpoperatingat2160rpm.Theworkingfluidiswaterandflowisassumedtobesteadyandincompressible.Duetorot

ationalperiodicityasinglebladepassagewillbemodeled.Theinitialflow-fieldwillbesolvedwithoutcavitation.Itwillbeturnedonlater.ANSYS,Inc.Proprietary©2009

ANSYS,Inc.Allrightsreserved.WorkshopSupplementWS5:CavitatingCentrifugalPumpWS5-2April28,2009Inventory

#0025991.StartWorkbenchandsavetheprojectascentrifugalpump.wbpj2.DragCFXintotheProjectSchematicfromtheCompo

nentSystemstoolbox3.StartCFX-PrebydoubleclickingSetup4.WhenCFX-Preopens,importthemeshbyright-clickingonMeshandselectingImportMesh>ICEMCFD5.Bro

wsetopump.cfx56.KeepMeshunitsinm7.ClickOpenWorkbenchANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreser

ved.WorkshopSupplementWS5:CavitatingCentrifugalPumpWS5-3April28,2009Inventory#002599Modifyingthematerialproperties:1.ExpandMate

rialsintheOutlinetree2.Double-clickWater3.OntheMaterialPropertiestabchangeDensityto1000[kg/m3]4.ChangeDynamicViscosityto0.001[kgm^-1s^-1]

underTransportProperties5.ClickOKCreatingWorkingFluidsANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.WorkshopSupplemen

tWS5:CavitatingCentrifugalPumpWS5-4April28,2009Inventory#002599SettinguptheFluidDomain1.Double-clickonDefaultDomain2.UnderFluidandParticleDe

finitions,deleteFluid1andthencreateanewFluidnamedWaterLiquid3.SetMaterialtoWater4.CreateanothernewFluidnamedWaterVapour5.NexttotheMaterialdro

p-downlist,clickthe“…”icon,thentheImportLibraryDataicon(ontherightoftheform),andselectWaterVapourat25CundertheWaterDataobject–ClickOK6.BackintheMater

ialpanel,selectWaterVapourat25C–ClickOKANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.WorkshopSupplementWS5:CavitatingCentri

fugalPumpWS5-5April28,2009Inventory#002599SettinguptheFluidDomain7.SettheReferencePressureto0[Pa]8.SetDomainMotiontoRotating9.SetAngularVelocit

yto2160[revmin^-1]10.SwitchonAlternateRotationModel11.MakesureRotationAxisunderAxisDefinitionissettoGlobalZ11.SwitchtotheFluidModelstab,andse

tthefollowing:12.TurnonHomogeneousModelintheMultiphasesection13.UnderHeatTransfersettheOptiontoIsothermal,withaTemperatureof25C

14.SetTurbulenceOptiontoShearStressTransport15.ClickOKANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.WorkshopSupplemen

tWS5:CavitatingCentrifugalPumpWS5-6April28,2009Inventory#002599InletBoundaryCondition1.InsertaboundaryconditionnamedInlet2.OntheBasicSettingstab,se

tBoundaryTypetoInlet3.SetLocationtoINLET4.SetFrameTypetoStationary5.SwitchtotheBoundaryDetailstab6.Spe

cifyMassandMomentumwithaNormalSpeedof7.0455[m/s]7.SwitchtotheFluidValuestab8.ForWaterLiquid,settheVolumeFractiontoaValueof19.ForWaterVapour,s

ettheVolumeFractiontoaValueof010.ClickOKANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.WorkshopSupplementWS5:CavitatingCentrifugalPumpW

S5-7April28,2009Inventory#002599OutletBoundaryCondition1.InsetaboundaryconditionnamedOutlet2.OntheBasicSettingst

ab,setBoundaryTypetoOpening3.SetLocationtoOUT4.SetFrameTypetoStationary5.SwitchtotheBoundaryDetailstab6.SpecifyMassandMomentumusin

gEntrainment,andenteraRelativePressureof600,000[Pa]7.EnablethePressureOptionandsetittoOpeningPressure8.SetTurbulenceOptiontoZeroGradient9.Switchtothe

FluidValuestab10.ForWaterLiquid,settheVolumeFractiontoaValueof111.ForWaterVapour,settheVolumeFractiontoaValueof012.ClickOKANSYS,In

c.Proprietary©2009ANSYS,Inc.Allrightsreserved.WorkshopSupplementWS5:CavitatingCentrifugalPumpWS5-8April28,2009Inventory#002599Perio

dicInterface1.ClicktocreateanInterface,andnameitPeriodic2.SettheInterfaceTypetoFluidFluid3.ForInterfaceS

ide1,settheRegionListtoDOMAININTERFACE1SIDE1andDOMAININTERFACE2SIDE1(usethe“…”iconandtheCtrlkey)4.ForInterfaceSide2,settheRegionListtoDOMAIN

INTERFACE1SIDE2andDOMAININTERFACE2SIDE25.SettheInterfaceModelsoptiontoRotationalPeriodicity6.UnderAxi

sDefinition,selectGlobalZ7.SetMeshConnectionOptionto1:18.ClickOKANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.WorkshopSupplementWS5:Cavitat

ingCentrifugalPumpWS5-9April28,2009Inventory#002599WallBoundaryConditions1.InsertaboundaryconditionnamedStationa

ry2.SetittobeaWall,usingtheSTATIONARYlocation3.OntheBoundaryDetailstab,enableaWallVelocityandsetittoCounterRotatingWall4.Clic

kOK5.IntheOutlineTree,right-clickontheDefaultDomainDefaultboundaryandrenameittoMoving–ThedefaultbehaviorfortheMovingboundarycondition

istomovewiththerotatingdomain,sothereisnothingthatneedstobesetANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.WorkshopSupplementWS5:Cav

itatingCentrifugalPumpWS5-10April28,2009Inventory#002599Initialization1.Clicktoinitializethesolution2.OntheFluidSetting

sform,setWaterLiquidVolumeFractiontoAutomaticwithValue,andsettheVolumeFractionto13.SetWaterVapourVolumeFractiontoAutomaticwithValue

,andsettheVolumeFractionto04.ClickOKANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.WorkshopSupplementWS5:CavitatingCentri

fugalPumpWS5-11April28,2009Inventory#002599SolverControl1.DoubleclickSolverControlintheOutlinetree2.

SetTimescaleControltoPhysicaltimescaleAcommonlyusedtimescaleinturbomachineryis1/omega,whereomegaistherotationrateinradianspersecond.Youca

nuseanexpressiontodetermineatimestepfromthis.Inthiscase,2/omegawillbeusedtoachievefasterconvergence.3.Enterth

efollowingexpressioninthePhysicalTimescalebox:1/(pi*2160[min^-1])4.SetResidualTargetto1e-55.OntheAdvancedOptionstab,tur

nonMultiphaseControl,thenturnonVolumeFractionCouplingandsettheOptiontoCoupled6.ClickOKANSYS,Inc.Proprietary©2009ANSYS,Inc.Al

lrightsreserved.WorkshopSupplementWS5:CavitatingCentrifugalPumpWS5-12April28,2009Inventory#002599Out

putControl1.DoubleClickonOutputControlintheOutlinetree2.OntheMonitortab,turnonMonitorOptions3.UnderMonitorPointsandExpressions,

createanewobjectandcallitInletPTotalAbs4.SetOptiontoExpression5.Specifythefollowingexpression:massFlowAve(TotalPressureinStn

Frame)@Inlet6.CreateanewobjectcalledInletPStatic,andsetOptiontoExpression7.Specifythefollowingexpression:areaAve(Pressure)@Inlet8.Cl

ickOKANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.WorkshopSupplementWS5:CavitatingCentrifugalPumpWS5-13April28,2009Inventory#002599Solver1.C

loseCFX-PreandswitchtotheWorkbenchProjectwindow2.Savetheproject3.NowdoubleclickonSolutionintheProjectSchematictostart

theSolverManager4.WhentheSolverManageropens,clickStartRun5.Whenthesolutionhascompleted,closetheSolverManagerandreturntotheProject

window6.SavetheprojectANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.WorkshopSupplementWS5:CavitatingCentrifugalPumpWS

5-14April28,2009Inventory#002599Post-processing1.ViewtheresultsinCFD-PostbydoubleclickingResultsintheProjectSchematic2.In

sertaContourbyclicking3.FortheLocation,click,expandRegionsandthenselectBLADE4.SetVariabletoAbsolutePressurefromtheextendedlist5.SetRan

getoGlobal6.OntheRendertabswitchoffLightingandShowcontourLines7.ClickApplyANSYS,Inc.Proprietary©2009ANSYS,In

c.Allrightsreserved.WorkshopSupplementWS5:CavitatingCentrifugalPumpWS5-15April28,2009Inventory#002599Post-processing9.InsertanotherContouro

ntheHUBlocation,usingthevariableAbsolutePressurecolouredbyLocalRange.TurnoffLightingandShowContourLines.10.InsertanotherCon

tourontheSHROUDlocation,usingthevariableAbsolutePressurecolouredbyLocalRange.TurnoffLightingandShowCo

ntourLines.TheminimumpressureisabovetheSaturationPressureof2650PaforWaterhere.Inthenextstep,theoutletpressurewillbered

ucedenoughtoinitiateCavitation.ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.WorkshopSupplementWS5:CavitatingCentr

ifugalPumpWS5-16April28,2009Inventory#002599AddinganotherAnalysis1.CloseCFD-PostandreturntotheProjectSchematic2.ClickthearrownexttotheAcelland

selectDuplicate–AnewCFXprojectiscreatedasacopyofthefirst3.ChangethenameofthenewSimulationtoCavitation4.UsethearrownexttotheAcelltoRenameitt

oNoCavitation5.SavetheProject6.Double-clickSetupfortheCavitationsimulationtoopenCFX-PreANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.Wo

rkshopSupplementWS5:CavitatingCentrifugalPumpWS5-17April28,2009Inventory#002599PhysicsModifications1.EdittheDefaultDomain2.OntheFluidPairModelstabse

tMassTransfertoCavitation3.SetOptiontoRayleighPlesset4.TurnonSaturationPressure5.SetaSaturationPressureof2650[Pa]6.ClickOK7.EdittheOu

tletBoundaryCondition8.OntheBoundaryDetailstab,settheRelativePressureto300,000[Pa]9.ClickOKMostcavitationsolutionsshouldbeperforme

dbyturningcavitationonandthensuccessivelyloweringthesystempressureoverseveralrunstomoregraduallyinducecavitation.Tospeedupt

hisworkshop,asuddenchangeinpressureisintroduced.Notethatthisapproachmaynotbesuitableformodellingsomeindustrialcases.A

NSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.WorkshopSupplementWS5:CavitatingCentrifugalPumpWS5-18April28,2009Inve

ntory#002599PhysicsModifications1.EditSolverControl2.SettheMax.Iterationsto1503.SettheResidualTargetto1e-44.ClickOK5.CloseCFX-Preandsavetheproject6

.IntheProjectSchematic,dragcellA3ontocellB3–Thenon-cavitatingsolutionwillbeusedastheinitialguessfort

hecavitatingsolution7.Double-clickSolutionfortheCavitationsystem–IntheSolverManagernotethattheinitialconditionshavebeenprovidedfromthepr

ojectschematic8.ClickStartRunANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.WorkshopSupplementWS5:CavitatingCentrifugalP

umpWS5-19April28,2009Inventory#002599CavitationSolutionThereisasignificantspikeinresiduals,inpartduetoth

eoutletpressuredifference,butalsoduetothefactthattheabsolutepressureislowenoughtoinducecavitation.1.Whenth

eruncompletes,closetheSolverManagerandreturntotheProjectSchematic2.Savetheproject3.Double-clickResultsfortheCavitationprojecttoopenCFD-

PostANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.WorkshopSupplementWS5:CavitatingCentrifugalPumpWS5-20April28,2009Inventor

y#002599Post-processing1.Ifitisnotenabled,turnonvisibilityfortheWireframeandturnoffvisibilityforanyUserLocationsandPlots2.CreateanXYPlaneatZ=0.01[

m]3.ColouritbyAbsolutePressure(thevariableisavailableintheExtendedListbyclicking).UseaGlobalRange–Theminimumabsolutepressureiseq

uivalenttotheSaturationPressurespecifiedearlier,whichisastronghintthatsomecavitationhasoccurred4.ChangetheColourVariabletoWaterVapour.VolumeFraction5

.ChangetheColourMaptoBluetoWhiteANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.WorkshopSupplementWS5:CavitatingCentrifugalPumpWS5-21April28

,2009Inventory#002599Post-processing1.TurnoffvisibilityforPlane12.CreateaVolumeusingtheIsovolumemethod3.SettheVariabletoWaterVapour.Volume

Fraction4.SetModetoAboveValue,andenteravalueof0.55.Toview360degreesofthemodel,double-clickDefaultTransform6.UncheckInstancingInfofromDoma

in7.Set#ofcopiesto58.Set#ofPassagesto59.ClickOKANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.WorkshopSupplementWS5:Cav

itatingCentrifugalPumpWS5-22April28,2009Inventory#002599Post-processingThemainareaofcavitationexistsbetweenthesuctionsideofthebladeandtheshroudinthi

sgeometry.AsecondaryareaofcavitationisjustbehindtheleadingedgeofthebladeonthepressuresideFurtherstepstotry:1.CalculatetorqueontheBLADEusingthefu

nctioncalculator(hint,usetheextendedregionlisttofindtheBLADE,anduseGlobalZaxis)2.PlotvelocityVectorso

nPlane1,usingthevariableWaterLiquid.VelocityinStn.Frame3.Calculatethemassflowthroughthepump(hint:usethefunction

calculatortoevaluatemassFlowattheOutletregion)4.Usingasimilarmethodtostep2,calculatethedropinTotalPressurefromI

nlettoOutlet5.PlotStreamlines,startingfromtheInletlocation