帶前緣氣冷的旋轉(zhuǎn)渦輪流場(chǎng)實(shí)驗(yàn)與數(shù)值研究的中期報(bào)告

帶前緣氣冷的旋轉(zhuǎn)渦輪流場(chǎng)實(shí)驗(yàn)與數(shù)值研究的中期報(bào)告Abstract:Thisreportpresentstheprogressmadeintheexperimentalandnumericalinvestigationofaswirlingflowfieldwithaleading-edgeaircoolingsystemforturbomachineryapplications.Theexperimentalsetupisaclosed-loopwindtunnelfeaturingaseven-bladetestrotor,astator,andacoolingsystemconsistingofanarrayofsmallholesalongtheleadingedgeoftherotorblades.Theflowfieldischaracterizedbyastrongaxial-symmetricvortexcoreandasecondaryunsteadyvortexsystemthatinteractswiththebladeboundarylayersandthecoolingjets.Thevelocityandtemperaturefieldsaremeasuredusingavarietyofnon-invasivemeasuringtechniques,suchashot-wireanemometry,infraredthermography,andparticleimagevelocimetry.ThenumericalsimulationsarebasedonahybridReynolds-averagedNavier-Stokes/large-eddysimulationmethodologythatcapturestheunsteady,turbulent,andcompressibleflowphysics.Thenumericalandexperimentaldataarecomparedandanalyzedtorevealtheflowfeatures,theeffectsofcooling,andtheperformanceofthetestrotor-statorsystem.Theresultsshowthatthecoolingsystemsignificantlyreducesthebladesurfacetemperatureandenhancestheoverallperformanceofthesystem,especiallyathighrotorspeedsandlowflowrates.Introduction:Turbomachinery,suchasgasturbines,compressors,andturbofans,arecriticalcomponentsinmanyindustrialandtransportationapplicationsandplayakeyroleinenergyconversion,propulsion,andair-conditioningsystems.Thedesignandoptimizationofturbomachinerydependonathoroughunderstandingoftheflowphysics,includingtheaerodynamics,heattransfer,andthermo-mechanicalcoupling,particularlyinthepresenceofcomplexflowpatterns,suchasswirl,separation,andturbulence.Inaddition,thethermalloadinganddurabilityofthebladesandtheoverallsystemdependontheefficientcoolingofthehotgasandthebladesurface.Therefore,itisessentialtodevelopandvalidateadvancedexperimentalandnumericalmethodsforstudyingtheswirlingflowfieldandthecoolingsysteminturbomachinery.Theobjectiveofthisstudyistoinvestigatetheflowfieldandthecoolingsystemofatestrotor-statorsystemwithleading-edgeaircoolingusingexperimentalandnumericalmethods.Specifically,thestudyaimsto:1.Characterizethestructureanddynamicsoftheswirlingflowfield,includingthevortexcore,thesecondaryvortexsystem,andtheflowinteractionswiththebladeboundarylayersandthecoolingjets.2.Evaluatetheperformanceofthetestrotor-statorsystem,includingtheaerodynamicefficiency,themechanicalloading,andthethermalbehavior.3.Validateandimprovethenumericalsimulationmethodologyfortheswirlingflowfield,includingtheturbulencemodeling,theboundaryconditions,andthemeshquality.ExperimentalSetup:Theexperimentalsetupconsistsofaclosed-loopwindtunnel,aseven-bladetestrotor,astator,andaleading-edgeaircoolingsystem.Therotorandstatorhaveadiameterof0.3mandachordlengthof0.05m.Thebladesaretwistedatapitchangleof25degreesandhaveaconstantthicknessof0.004m.Thecoolingsystemconsistsofanarrayof87holes(0.002mindiameter)evenlyspacedalongtheleadingedgeofeachblade.Theholesareconnectedtoacompressedairsupply(upto10bar)andcanbeadjustedtovarythecoolingrateandthedistribution.Thewindtunnelisdesignedtoprovideacontrolledanduniformflowwithamaximumvelocityof60m/sandamaximumReynoldsnumberof1E+6basedonthebladechordlength.Theflowisseededwithsmokeparticlesforvisualizationandparticleimagevelocimetrymeasurements.Thetemperatureiscontrolledbyaheaterandacoolingcoiltomaintainaconstanttestsectiontemperatureof20degreesCelsius.Thevelocityandtemperaturefieldsaremeasuredusingavarietyofnon-invasivemeasuringtechniques,suchashot-wireanemometry,infraredthermography,andparticleimagevelocimetry.Thehot-wireanemometermeasurestheinstantaneousvelocityfluctuationsinthreedirectionsusingaplatinumwire(0.002mindiameter)insertedintotheflowparalleltothebladesurface.Theinfraredthermographymeasuresthesurfacetemperaturedistributionofthebladesandthecoolingjetsusingahigh-speedinfraredcamera(1000frames/s).Theparticleimagevelocimetrymeasuresthevelocityvectorsoftheflowusingahigh-powerlaserandahigh-speedcamera(5000frames/s).Numericalsimulations:ThenumericalsimulationsarebasedonahybridReynolds-averagedNavier-Stokes(RANS)/large-eddysimulation(LES)methodology.TheRANSmodelisusedtocapturethemeanflowpropertiesandtheturbulenceeffectsonthebladesurfaceandthecoolingjets.TheLESmodelisusedtocapturetheunsteadyandcoherentflowstructures,suchasthevortexcoreandthesecondaryvortices.ThenumericalsimulationisperformedusingthecommercialsoftwareANSYSFluent.Thebladegeometryisdiscretizedusingastructuredmeshwith1millioncells.Themeshisrefinednearthebladesurfaceandtheholestocapturetheboundarylayerandthecoolingjets.Theinletandoutletconditionsaresettomatchtheexperimentalconditions,includingthevelocity,temperature,andturbulenceintensity.Theturbulencemodelisthek-omegashear-stress-transport(SST)model,whichiscalibratedusingtheexperimentaldata.ResultsandDiscussion:Theexperimentalandnumericalresultsshowthattheflowfieldischaracterizedbyastrongaxial-symmetricvortexcoreandasecondaryunsteadyvortexsystemthatinteractswiththebladeboundarylayersandthecoolingjets.Thevortexcoreislocatednearthecentralaxisandextendsabovethebladesurface.Thesecondaryvorticesaregeneratednearthebladetipandthecoolingholesandmoveintheoppositedirectiontothemainflow.Thesevorticesinteractwiththebladesurfaceandthecoolingjetsandcreatecomplexflowpatterns,suchasrecirculationzones,shearlayers,andturbulentspots.Theleading-edgeaircoolingsystemsignificantlyreducesthebladesurfacetemperatureandenhancestheoverallperformanceofthesystem,especiallyathighrotorspeedsandlowflowrates.Thecoolingrateandthedistributionhaveasignificantimpactontheflowfieldandthetemperaturedistribution.Thecoolingjetsinducealocalcoolingeffectandmodifytheflowpattern,particularlynearthebladetip.Thenumericalsimulationresultsagreewellwiththeexperimentaldataandprovideadditionalinsightsintotheflowphysics,suchasthedetailedvelocityandtemperaturefields,theturbulentfluctuations,andtheunsteadyvortexstructures.ThehybridRANS/LESmethodologycapturestheessentialfeaturesoftheswirlingflowfieldandprovidesareliableandefficientmeansforpredictingtheperformanceofthetestrotor-statorsystem.Conclusion:Thisreportpresentsthemid-termpro