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1、ExperimentalStudyofTurbulenceInfluenceonWindTurbinePerformanceMiguelTalavera,FangjunShuDepartmentofAerospaceandMechanicalEngineering,NewMexicoStateUniversity,LasCruces,NewMexico88003-8001,USAABSTRACTRegardingtheissueofunmatchedReynoldsnumbersfordownscaledwindturbinetestsinwi
2、ndtunnels,astudyoftheperformancecharacteristicsofamodelwindturbineoperatinginthewakeofanotherturbineofthesamemodelunderlaminarandturbulentinflowwasperformed.Thedistancebetweenthetwoturbineswassetat5,10,and15turbinediameters.Inthelaminarinflowcase,thewakeofthefrontturbineredu
3、cedtheefficiencyoftherareturbinegreatlyevenwhenthedistancewas15diameters.ThiswasduetoslowvelocityrecoveryinthelowReynoldsnumberwake.Tosolvethisissue,turbulentinflowiscreatedusinganactivegridsysteminstalledbetweenthecontractionandtest-sectionofthewindtunnel;themaximumturbulen
4、ceintensitycanreach20%.Velocityfieldsupstreamandinthewakeoftheturbineweremeasuredusinga2D-PIVsystem;1000pairsofimageswereacquiredforeachlocationtoachievestatisticalconvergence.Itwasfoundthatbyusingturbulentinflowtheefficiencyofboththeupstreamandthedownstreamturbinewashighlyi
5、mproved.FlowseparationinthesuctionsidethewindturbinebladewasstudiedusingPIVunderlaminarandturbulentflowforasingleturbine,anditwasfoundthatthewindturbineefficiencywasdirectlyrelatedtothisphenomenasincethelaminarcasepresentedmoreflowseparation.Itwasalsofoundthattheefficiencyof
6、bothturbinesishighlyrelatedtotheturbulenceintensityintheinflow.Ataconstanttipspeedratiofortheupstreamturbine,theefficiencyforthedownstreamturbinewas4.1timeshigherthaninlaminarcasewhentwoturbinesareseparatedby5diameters;for10and15diameterswiththesameconditionsitwas2.71,and2.4
7、8timeshigherrespectively.Themaximumefficienciesreachedforthedownstreamturbinewere38.5%,34.5%,and24.6%for15,10,and5diametersofdistancerespectively,thisresultsisclosetothedesignpowercoefficient.Therefore,despitethelowReynoldsnumberarealisticflowsimilartothefieldcanbereachedusi
8、ngturbulentflowcreatedbyanactivegridsystem.INTRODUCTIONWindtunneltestsofwin
