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1、上海交通大学硕士学位论文ABSTRACTNumericalInvestigationofFlowandHeatTransferforGasTurbineRotorTipABSTRACTInhotpartsofgasturbines,thebladetipissubjecttohightemperatureandhighheattransferrate,whichcancauseburningandgreattemperaturegradientandthelifeofbladesisdirect
2、lyaffected.Thecharacteristicsofflowandheattransferofrotortiparestudiedinthispaper.3NumericalsimulationsareperformedforthefirstrotortipofEturbine,whichwasanenginedesignedbyGE.Fourturbulencemodelsareused.Theeffectsontheflowandheattransferofdifferentrot
3、ortipgap,anddifferentconfigurationsincludingflattipandsquealertip,isinvestigated.Thenumericalresultswithdifferentturbulencemodelsarecomparedtofindthemostsuitableoneforthecurrentapplication,whichcontributestocomputationofthetipfilmcooling.Theworkandre
4、sultsarelistedbelow.Tofindtheadvantagesofsquealertip,theresearchabouttheflattipisstudiedfirst,includingthetipleakageflowanditseffectontheheattransferofbladesurface(suctionandpressureside)nearthetipregion.Fourturbulencemodelsk-ε，RNGk-ε、k-ωandSST,areap
5、pliedinthisresearch.Resultsshowthatthestandardk-εmodeloverpredictstheheattransferrateandtheSSTmodelunderpredictsit,whiletheresultsusingtheothertwomodels(RNGk-εandk-ω)arerelativelybetter.Forthesquealertip,thestandardk-εmodelandk-ωmodelaremoresuitable.
6、Basedontheaboveconclusions,thek-ωmodelisadopted.Forbothtipconfigurations,threetipclearancevalues,1.31mm，1.97mm，3.29mm(1%、1.5%、2.5%bladeheight)areinvestigated.Resultsshowthatwiththeincreaseoftipclearance,themassflowrateoftipleakageflowincreases.Thepre
7、ssurecoefficientofprofilesbelow90%bladeheightisalmostthesame.At97%cuttingplane,thepressureIII万方数据上海交通大学硕士学位论文ABSTRACTcoefficientofmiddlepartofthesuctionside(regioninfluencedbytheleakagevortex)ishigherthanthatforthesquealertip,whichshowsthatthesqueale
8、rtipactsasalabyrinthseal,whichincreasesthedragoftheleakageflow.Sothedecreaseoftipclearanceandsquealertipareeffectivewaystoreducethetipleakageflow.Withtheincreaseofbladetip,theheattransfercoefficientincreases.Underthesameclearance,theaveragedheattrans
