english_跨音速風(fēng)扇葉尖間隙對(duì)顫振特性的影響研究

1、TheinfluenceoftipclearanceonrotflutteracteristicsYANGJun，ZHENGYun（Schoolofenergypowerengineering，BeiHangUniversity，Beijing，100191，China）Abstract:Thepurposeofthispaperistousenumericalsimulationmethodtoresearchtheinfluence

2、offanbladetipclearancesizeonbladeflutteracteristics.TheNASArot67wastheexampleestablishedasinglerowofannularflowmodel.ThesteadyunsteadyflowfieldsaresolvedbyusingtheReynoldsaveragedNavierStokesequation（RANS），thestructurald

3、ynamicequationsaresolvedusingthemodalsuperpositionmethod.TheHGFScalculationprogramisusedtocalculatetheflowfieldaerodynamicdamping.Thebladetipclearancesizewas0.15%spanto1.26%span.Numericalresultsshowthattipclearancesizeae

4、rodynamicdampingisNonlinearity.Thereexistsadletipclearancemaketheaerodynamicdampingmaximumaeroelasticstabilityoptimal.Keywds:tipgapleakagevtexflutteraeroelasticstability0引言Withthedevelopmentofmodernaircraftengineshigherr

5、equirementswasputfwardtoengineperfmance.Ontheonehhighenginethrustweightratiolightweightacteristicswasrequired.Ontheotherhhighreliabilitylonglifelowfuelconsumptionresultinginfluidinducedvibrationproblemsincreasing.Aeroeng

6、inerotbladeflutterisaselfexcitedvibration.Sincethefluiddopositivewkonasolidfieldtheaerodynamicfcesenergyontherotbladescan’tbeabsbedbladeflutterwillhappen[1][2].Tipclearanceleakageflowchannelshockleafboundarylayeritsinter

7、actionisacterizedbythefmationofacomplexthreedimensionalunsteadyflowinthevicinityoftherotbladetip[3].Theresearchoftipclearanceflowstheirimpactontheflutteracteristicsshowthatthepresenceoftipleakageflowwillnotonlychangetheb

8、ladesurfacepneumaticpowerdistribution[4]butalsothetipleakageflowunderlargegapmayincentiveflutteroccurred.Studyoftipclearanceaeroelasticstabilityoftherotisnounifiedconclusion.HuZongaal[5]madeaflutterexperimentationattwodi

9、fferenttipclearanceinatransoniccompresstestbedofBF1seriesrot.Theresultsshowthatundersmalltipclearanceduetothesecondaryflowlossisreducedgasexcitationenergyincreasesthebladestallflutterareaexpedflutterboundaryfward.Lietal[

10、6]discussestherelevanceofthecompressrotbladeleakflowvtexaeroelasticstability.Theresultsshowedthatleakagevtexaffectsthebladeaeroelasticstability.Largeeddyleakagevtexcaninhibittheoccurrenceofbladeflutter.Yangetal[7]identif

11、iedtheimpactofcompressbladetipclearancetoaeroelasticstability.Foundthatwithoutconsiderthevalueofthetipclearancemaygivetoostablebladeflutterpredictionresult.Caetano[8]calculatedtheeffectsofmultistageaxialcompressrotblades

12、bladetipclearancestatvanesgaptoflutteracteristics.Theresultsshowthattheflowgeneratedbyalargetipclearancegapinducingflutter.Sers[9]throughexperimentalstudiesnumericalsimulationsillustratealargertipclearancehaveagreatimpac

13、tonaerodynamicdamping.Fuetal.[]Useacteristicvaluesoftheenergymethodcalculatedthechangeofcompressbladeaeroelasticstabilityunderdifferentgapstheresultsshowedthatasthegapincreasestheaeroelasticstabilityofthefirstbladebecome

14、ssmallerreachingaminimumvaluetheybecomelargethereisanoptimumsizeofthetipclearance.Changesinsurfacepressurebladesaerodynamicdampingofthisarticlewillcausethegapbyanalyzing1.2固體域的求解固體域的求解Solvingequationsusingstructuraldynam

15、icsmodalsuperpositionmethodvariousmodesfthcomingobtainedfrommodalanalysisaremultipliedbythecrespondingconstantcoefficientsaresuperimposedtoobtainthedynamicresponse.Thegistofitbefeintegratingtheequationsofmotiontheequatio

16、nsofnaturalmodesofvibrationofthefreeuseofthesystemisconvertedtothenmutuallycoupledequationstheseequationscanberesolvednumericallyintegrated.Whenusingnumericalmethodsfeachequationyoucanusedifferenttimesteps.Thesetwocombin

17、emedirectintegrationmethodhasagreatadvantagewhencalculatingtheanalysistimeislongerbutonlyasmallnumberoflowdermodeshapesresultmesuitableftheuseofthemodalsuperpositionmethod.Definitionofnaturalmodes:。（2）Φ=[12…]Semipositive

18、definitenessstiffnessmatrixbythequalityofthepositivedefinitenessofthematrixshowsthat:。（3）T[]Φ=1≤≤[T]=1≤≤[]=[]Wherein[M_g]themainqualitymasterrigidity[K_g]calledthesystemalsoknownasgeneralizedmassgeneralizedstiffness.m_ik

19、_irespectivelycrespondingtotheimodalgeneralizedmassgeneralizedstiffness.Thenaturalvibrationofthemainqualityvectφbenmalizedfmula(1.3)canbesimplifiedas:。（4）T[]Φ=T[]Φ=1≤≤[2]Codinatetransfmationisintroducedthesystemofgeneral

20、izedcodinatesthephysicalrelationshipbetweencodinatesdefinedas：。（5）=ΦSofar.EquationsvibrationbecameNlinearlyindependentdinaryDifferentialEquations:。（6）[][g]=gWhereinQ_ggeneralizedaerodynamicfceconstitutedbythecrespondingr

21、espectivemodalmodalfcevect.Generalizeddisplacementofthefmula(6)inwhichNindependentgroupofindependentlineardinarydifferentialequationsusingnumericalmethods(fourfourthderRungeKuttamethod)canbeobtainedaftersolvingthecrespon

22、dingsystemofeachmodewhichislinearlysuperimposedtoobtainthetotalmodalshiftstructure.Finallythefmula(5)togettheactualphysicaldisplacementofthestructure.1.3計(jì)算模型計(jì)算模型ChosennumericalmodelparametersfromNASARot67[][].Rot67fNASAd

23、esignedasmalltransonicenginefanthepaperedpartsofitsfanrotblades.ContrastIndertounifytheresultsofboundaryconditionstotalimptsgivenmoderatetotalpressurecasinghubfthenoslipwallconditions.Steadychannelcalculationusingperiodi

24、cboundaryconditionsexptsgivenstaticpressureatthehubrotacteristiccurvesobtainedunderdifferentgaps.Fullcirculationsolidcouplingcalculationsetflowoutletboundaryconditionsunderdifferentaerodynamicdampingobtainedclearancerot.

25、Rot67longestbladeradius16.16cmdesigntipclearanceis1.016mmapproximately0.63%ofbladeradius(referredtoas0.63%span).Steadychannelcalculationsfullcirculationsolidcouplingcalculationedgaprangeis0.15%span~1.86%span.Fluidsoliddo