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1、JournalofWindEngineeringandIndustrialAerodynamics,39(1992)151-160151ElsevierSciencePublishersB.V.,Amsterdam--PrintedinTheNetherlandsThickairfoilsforHAWTsW.A.Timmer~andR.P.J.O.M.vanRooyb"InstituteforWindEnergy,FacultyofCivilEngineering,DelftUniversityofTechnology,Stevinweg
2、1,2628CNDelft,TheNetherlandsbFacultyofAerospaceEngineering,DelftUniversityofTechnology,KluyverwegI,2629HSDelft,TheNetherlandsSummaryTwonew25%thickairfoildesignsarepresented,arootandamidspansectiondesignatedDU91-Wl-251andDU91-W2-250respectively.Calculationofthesmoothandrou
3、ghperformanceisdonewiththeXFOILcode.Comparisonsaremadewitha24.2%thickFFAairfoil.1.IntroductionOneoftheolderseriesofgeneralaviationairfoilscurrentlyusedinHAWTsistheNACA63series.TheseairfoilswithmoderatedesignliftcoefficientshavegoodI/dratiosandshowrathersmoothbehaviourarou
4、ndthepeakliftcoefficient,atleastforthesectionswiththicknessesof21%andbelow.AsthethicknessofNACA63-4XXandNACA63-6XXairfoilsisincreased,peakliftcoefficientsdecrease(Fig.1)andperformanceintheroughconditionbecomespoor.ThisbehaviourwasconfirmedbywindtunneltestsontheNACA63-425a
5、irfoil[1].WithintheframeworkoftheCECJouleprogrammeinitiallytheDelftcon-o63-4x×a63-4xxRc-:3x10A6Rc=6x10A62.O01.75AxE1.50¢J1.251.00i--,....i,.i...1015202.530tic(%)Fig.1.TheeffectofthicknessonthepeakliftcoefficientfortheNACA63-4xxseriesofairfoils[1,8],0167-6105/92/$05.00©199
6、2ElsevierSciencePublishersB.V.Allrightsreserved.152tributiontothecombinedworkwithENEAandtheUniversityofTorino,bothfromItaly,aimedatmodifyingthis25%thickairfoiltoreachabetterbehav-iourintheroughnosesituation.ThedecreaseinperformancewithincreasingthicknessfortheseNACAse-rie
7、scanbeattributedtothefactthatthethicknessdistributionisscaledaroundachosencamberline.Thisleadstohigheruppersurfacemaximumvelocitiesandadversepressuregradientsresultinginamoreforwardlocatedboundarylayerseparation,especiallyintheroughsituation.Simplymodifyingthethusscaledai
8、rfoilwouldnotprovetobesatisfactoryexceptwhentheentirepressuredistributionwouldberearranged.Itwas
