ChineseJournalofTurbomachinery第65卷，2023年第3期Http://turbo-jour.cftn.cnVol.65，2023,No.3EffectsofTurnShapesonFlowandHeatTransferEffectsofTurnShapesonFlowandHeatTransferCharacteriCharacteri-sticsinU-shapedChannelUnderRotatingConditionssticsinU-shapedChannelUnderRotatingConditions*Ru-quanYou1,2Ze-xuanLiu1,2,*Hai-wangLi1,2Jin-chengShi1,2ZhiTao1,2（1.ResearchInstituteofAero-Engine,BeihangUniversity；2.NationalKeyLaboratoryofScienceandTechnologyonAero-EnginesAero-Thermodynamics,BeihangUniversity)Abstract：Inthispaper,theflowandheattransfercharacteristicsinU-shapedchannelwiththreedifferentturnshapesarestudied.Therotationnumberrangesfrom0~0.251,Reynoldsnumberare11500,23000,34500,respectively.TheresultsshowthattheflowseparationandreattachmentintheturningsectionarethekeyfactorsaffectingthelocalheattransferandpressurelossofU-shapedchannel.Thesquareturnwillgeneratecornervorticesattheoutsideoftheturningsection,andthesizeoftheinnerseparationvortexandreattachmentvortexislargerthanthatoftheothertwoturnshapes.Theexistenceofvortexsystemwillincreasethemixingandenhanceheattransfer,butincreasethepressureloss,soitsrelativeNusseltnumberandpressurelossarethelargest.Therearecornervorticesontheoutsideoftheturningsectionofthechannelwithainnercircleturnandoutersquareturn,butthearc-shapedinneredgemakesitsseparationdelayandtheseparationvortexdecrease,andthesizeofthereattachmentvortexalsodecreases.Thearc-shapedouteredgeofthechannelwithcircleturninbothinnerandouterfurtherinhibitsthegenerationofcornervortices,soitsrelativeNusseltnumberandpressurelossarethelowest.RotationwillcausethefluidtodeflectundertheinfluenceofCoriolisforce,strengthentheheattransferonthetrailingsurfaceofradialoutflowandtheleadingsurfaceofradialinternalflow,andgeneratesecondaryflowandseparationvortexintheturningsection,resultinginthechangeofvortexstructureintheturningsection.Withtheincreaseofrotationnumber,theNusseltnumberofthethreetypesofturningsectionstructuresincreases.Thethermalperformancefactorofthethreechannelsincre...
