多级涡轮密封泄漏的数值模拟.pptx

多级涡轮密封泄漏的数值模拟.pptx

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,SimulationofSealLeakageinMultistageTurbine,author:

ruiYang2009-11-18,NUMECAINTERNATIONALUSERMEETING2009,IntroductionMotivation,LeakageFlowSimulationLabyrinthSealHoneycombSealBrushSealConclusionandSuggestion,ShanghaiElectricPowerGenerationGroupShanghaiBoilerWorksCO.,LTDShanghaiElectricPowerGenerationEquipmentCO.,LTD.ShanghaiPowerGeneratorCompanyShanghaiTurbineCompany（STC）,ShanghaiElectricAuxiliaryMachineryCompanyShanghaiElectricWindCO.,LTD,TheBiggestGroupofShanghaiElectricAccountfor70%ofTotalSalesAmount,STCPRODUCTS,STEAMTURBINE,GASTURBINE,COMBINEDGAS-STREAMCYCLETURBINE,NUCLEARPOWERTURBINE,135MW/300MW/400MW/600MW/1000MW/,Ratedpower:

ToImproveEfficiencyofTurbinesDesign&OptimizeperformanceofMainflowstructure:

InletChamber,optimizationofshapeofflowchannelreductionofinletpressurelossimprovementofpressure/temperaturedistortiononbladeinletsurface,Motivation:

InletValve,ExhaustHood,OriginalModel,RedesignedModel,straight,twisted,Blade3DSTM,3DVTM,Potentialimprovements?

LeakageLoss,BladeShapeLoss,SecondaryFlowLoss,Rotor/StatorInteractionLossCavityFlowLoss,BladeTipSealsLossRatio:

40%PowerLoss:

3149KWHeatConsumption:

71.7KJ/KWh,ShaftSealsLossRatio:

16%PowerLoss:

1618KWHeatConsumption:

28.5KJ/KWh,DiaphragmSealsLossRatio:

11%PowerLoss:

898KWHeatConsumption:

18.9KJ/KWh,BladeShapeLossRatio:

2%PowerLoss:

179KWHeatConsumption:

3.2KJ/KWh,SurfaceRoughnessLossRatio:

31%PowerLoss:

2765KWHeatConsumption:

54.9KJ/KWh,PowerandHeatLossFactorofHP/IPCylinder,Howtoreduceleakageloss?

ReasonsofEfficiencyLossCausedbySealsLeakageFlow:

DirectLoss:

massflowreductionofmainsteampartakingexpansioninbladepathandthusreductionofworkLossofbladeliftintheendsectionsandthusreductionofwork,IndirectLoss:

IncreasedincidenceondownstreamstagewithconsecutiveincreaseinsecondaryflowMixinglossoftipvortexandtipjetrespectively,Unshrouded,Shrouded,SealsUsedinSteam/GasTurbine:

LabyrinthSeal,HoneycombSeal,BrushSeal,LabyrinthSealsCharacters:

simplicityreliabilityeasyreplacementlowcost,Disadvantage:

limitedbymaterial,labyrinthsealsshouldkeeparelevantclearanceduringoperationsolargeleakageinfluencestheefficiencyofturbine,especiallyduringenginetransients,Toreduceleakagerate,honeycomb&brushsealusedmoreandmoreintheturbinemachinery.,Advantagescomparetolabyrinthseal：

Honeycombseals,rotoroutletbeforedrainoff,nextstageafterdrainoff,EFFICIENCY,0.08%,Unsaturated（wet）steamdomain,EXPERIMENT,TESTBENCH,TESTPIECE,NUMERICALSIMULATIONToInsureResultMoreAccuracyandOperateMoreConvenientWechoose:

LabyrinthSeaL,LeakageFlowSimulation:

1.09%,shroud43%diaphragmleakageinshroudis43%largerthanIndiaphragmallleakageflow（2.1kg/s）accountsfor0.83%ofmainstreamflow（254.4kg/s）,efficiencylosscausedbyleakageflowis1.09%inthisturbinestage,Flowlinesinlabyrinthseals:

pressuredropinaxialdirectionthrottlingeffectoftooth,NumericalSimulationStrategy:

Calculationdomain,HoneycombSeal,BladeStage,DiaphragmSeal,HoneycombSeal,NumericalSimulationStrategy:

MeshGeneration,AutoGrid5,iGG,iGG,SomeResultsofSimulation,SomeResultsofSimulation:

Velocityvectorsinaxialcuttingplane:

Vortexinhoneycomb:

Velocityvectorsatdifferentradialheight:

FlowdirectioninZ（axialdirection）,Withtheradialheightincreasing:

FlowdirectioninreverseaxialdirectionMagnitudeofvelocityDecreasedVortexesshaped,LeakageinDifferentSeals,Clearance:

0.75mm,Clearance:

0.2mm,OtherExample,HeadingPlateBackingPlate,BristlePack,BrushsealNumericalSimulationStrategy:

Geometry,MeshGeneration,2D,3D,ConnecttoblademeshinIGG,PorousMediaModel,DarcyLaw:

Themodelcanbeusedbyspecifyingthefollowingparameters:

TheporositywhichdependsonthestructureofthebristlepackThemeandiameteroftheinclusiondThenthepremeabilitykisgivenbytheCarman-Kozenyrelation:

Pressuredropsinbristlepack:

Flowlinesinbrushseal:

a,b,c,d,e,f,Conclusion:

Inturbinestage,leakageratesinfluenceflowefficiencydramatically.Analyzingtheleakageofdifferentsealsisveryusefultoenhancetheflowefficiency.NUMECAispowerfultosimulateleakageofsealsinturbineandtheflowdetailsarealsocapturedthroughCFD.Allofthesecanaidindesigninglowleakagesealstoenhancetheflowefficiency,Suggestions:

Forporousmediummodel:

Inthiscase,thepremeabilitykinaxialandradialdirectionisnotthesame.however,theporousmediumprovidedbyNUMECA,onlyonepremeabilitykcouldbesetted.sothepremeabilityisthesameinalldirection.Thisisnotverysimilarwiththephysicalphenomenon.,thisproblemcouldbesolvedbysettingpremeabilitykindifferentdirections,Suchasinthiscase:

inaxialdirection-KZinradialdirection-Kr,Forconvergenceofefficiency:

Forsteamturbine,condensable_water_steamischosedasfluidmodel.Andallth