OpenFOAM在叶轮机械中的应用

OpenFOAM®®andTurbomachinery:aDemonstrationofaSimplifiedFrancisTurbineGeometryA.Wouden,B.Lewis,J.Cimbala,E.PatersonThePennsylvaniaStateUniversityFundedbytheUSDepartmentofEnergy•Motivation•Somepreliminarybench-workCylindricalInletVelocityPatchforFoam•TheSimplifiedFrancisTurbine•TheComputationalDomain•TheOpenFOAM®Setup•TheNo-RunnerComputation•ResultsfrompotentialFoam,simpleFoam,simpleSRFFoam,MRFSimpleFoam2Motivation•ThestudyofflowthroughaFrancisturbineiscomplex•Anunderstandingofpre-processingmethodologyisuseful•AsimplifiedFrancisturbinedemonstratesthemethodologywithoutthecomplexgeometry•TheresultingOpenFOAM®casestructureprovidesanarchetypeforotherhydroturbineapplications3CylindricalInletVelocityPatchAdaptedfromOpenFOAM®1.7.4Theinletvelocitypatchaltersthevariablelist.OpenFOAM®1.7name{typecylindricalInletVelocity;axis(001);centre(000);axialVelocity30;rpm100;radialVelocity-10;}Modification5name{typecylindricalInletVelocity;axis(001);centre(000);axialVelocity30;tangentVelocity10;radialVelocity-10;}•Givenaninletsurfacename,thevelocity(0/U)canbespecifiedincylindricalcoordinates.ThemodificationcorrectsanerrorinOF1.7versionofcylindricalinletvelocity.OpenFOAM®1.7Modification6•Normalizedradialvector;noscaling•r-componentscaledbyradiusTheinletconditioniscombinedwithSRFVelocitytoworkwithsimpleSRFFoam.7SRFcylindricalInletVelocity•SRFVelocity“Ifrelative,includetheeffectsoftheSRF”[1]•cylindricalInletVelocitySpecifyboundaryincylindricalcoordinates•SRFcylindricalInletVelocitySpecifyboundaryincylindricalcoordinates,and“Ifrelative,includetheeffectsoftheSRF”name{typeSRFcylindricalInletVelocity;relativeyes;axis(001);centre(000);axialVelocity30;tangentVelocity10;radialVelocity-10;}SRFVelocitycylindricalInletVelocityforFoam:InitialConditionUtilityCreatedasasemi-automatic(user-interactive)OpenFOAM®utility.8AFortran-basedutilitycreatesinitialconditionfiles.•MotivationCreaterun-readyinitialconditionfilesProvideuserinteraction•Automatedefinitesurfacetypes•Promptambiguoussurfacetypes(i.e.typepatch)•Rememberuserresponses9kforFOAMUpωTheSimplifiedFrancisTurbineAdaptedfromGAMMFrancisturbinegeometry.10Disclaimer•Thegeometryofthisturbine,thoughbasedonatheGAMMFrancisturbine,doesnotrepresentanyactualturbineinoperation;therearenoexperimentaldataavailable.•Rather,thesimplergeometryprovidesforatutorialtoturbomachineryanalysisinOpenFOAM®11TheturbinehousingisidenticaltotheGAMMgeometry.•StatorRingOuterDiameter:692mmInnerDiameter:334mmAltitude:120mm•BandTopDiameter:422mmBottomDiameter:402mmAltitude:99mm12•CrownOuterDiameter:334mmInnerDiameter:44mmAltitude:134mm•DiffuserMinDiameter:402mmMaxDiameter:490mmAltitude:446mmThestaybolt,wicketgate,andrunnerbladehavesomegeometricequivalencetoGAMM.•StayBoltReducedtocircularcylinderDiameter:12mm•WicketGateReducedtoroundedflatplateChord:73mmThickness:9mm•RunnerBladeReducedtoroundedflatplateThickness:6mm13(Nottoscale)ddLtLtt(Nottoscale)tThecomputationaldomainincludesthe360°profile.•StayRow#ofblades:20Periodicity:18°•WicketRow#ofblades:20Periodicity:18°•RunnerPassage#ofblades:13Periodicity:27.69°14TheComputationalDomainCADcreatedinSolidWorks®MeshgeneratedinPointwise®.15Themeshconsistsoffourindependentlybuiltregions.•StayVaneZone502,080cellsy+min=15.82•WicketGateZone1,171,200cellsy+min=20.1416•RunnerBladeZone1,117,090cellsy+min=3.97•DiffuserZone23,520cellsy+min=90.20ggi:C`OutletSlipWallggi:A`ggi:BInletggi:Aggi:B`ggi:CTheOpenFOAM®SetupUsingOpenFOAM®1.6-ext.17TheAllrunscriptcontainsastep-by-stepprocessoftheOpenFOAM®operations.•Consistsoffivesteps1.Zoning•identifynonOrthoFacezones•createggizones•defineMRFzones2.Initializing•retrieveresultsfromaprevioussolution3.Decomposing•dividemeshforparallelcomputing4.Executing•runthesolver5.Reconstructing•recombineresultsfortheconvergedtimestep18Theresidualscanbetrackedbyconstructingagnuplotscript.19TheOpenFOAM®setupisconsistentbetweensolvers.•ThesimplifiedturbineOpenFOAM®casemaintains1.k-ωSSTturbulencemodel2.Steady-state,Gauss-linearfinitevolumeschemes3.GAMGsolveronpressure4.smoothSolveronvelocityandturbulenceparameters5.smallunder-relaxationfactors•p=0.2•U=0.3•k=0.3•ω=0.320TheNo-RunnerComputationFindingtherightRPM.21TheRPMiscalculatedthroughvelocitytrianglesattheleadingedge.22•Fromtextbookformulation[3],•Solvingfortheangularspeed:•Byconvention,•AndconvertingintoRPM:Therpmisdeterminedthroughprocessingtheno-runnergeometry.•ProcessedusingsimpleFoam•Forthesimplifiedturbinerpm=363.3223•VelocityWaypointpotentialFoamInitializingtheflowfield.24PreliminaryprocessinginpotentialFoamsetsaninitialvelocitydistribution.•ConvergenceCriterionPressureresidualdecreasesbythreeordersofmagnitude•ParameterUpdateVelocityfielddataareupdatedto0/UOtherfielddataareunaffected25Swirlcomponentattheinletseemstodisappearinsidethecomputationaldomain.26InletflowdirectionsimpleFoamAnalysisofanon-rotatingturbine.27Theglobalconvergencecriterionindicatesadequateconvergence.•Theholdingtorque,(Mz)convergesto550N-m28•Relativeresidualsd