风力涡轮机的空气动力学

AerodynamicsofWindTurbinesSecondEdition3212J&JAerodynamicTurbines15/11/071:42PMPagei3212J&JAerodynamicTurbines15/11/071:42PMPageiiAerodynamicsofWindTurbinesSecondEditionMartinO.L.HansenLondon•Sterling,VA3212J&JAerodynamicTurbines15/11/071:42PMPageiiiSecondeditionpublishedbyEarthscanintheUKandUSAin2008FirsteditionpublishedbyJames&James(SciencePublishers)Ltdin2000Copyright©MartinO.L.Hansen,2008AllrightsreservedISBN:978-1-84407-438-9TypesetbyFiSHBooks,EnfieldPrintedandboundintheUKbyTJInternational,PadstowCoverdesignbyNickShahForafulllistofpublicationspleasecontact:Earthscan8–12CamdenHighStreetLondon,NW10JH,UKTel:[phone]Fax:[phone]Email:[e-mail]:—2nded.p.cm.ISBN-13:978-1-84407-438-9(hardback)ISBN-10:1-84407-438-2(hardback)1.Windturbines.2.Windturbines—Aerodynamics.I.Title.TJ828.H352007621.4’5—dc222007011666ThepaperusedforthisbookisFSC-certifiedandtotallychlorine-free.FSC(theForestStewardshipCouncil)isaninternationalnetworktopromoteresponsiblemanagementoftheworld’sforests.3212J&JAerodynamicTurbines15/11/071:42PMPageivContentsListofFiguresandTablesvi1GeneralIntroductiontoWindTurbines122-DAerodynamics733-DAerodynamics1841-DMomentumTheoryforanIdealWindTurbine275ShroudedRotors416TheClassicalBladeElementMomentumMethod457Control/RegulationandSafetySystems638Optimization789UnsteadyBEMMethod8510IntroductiontoLoadsandStructures10311BeamTheoryfortheWindTurbineBlade10712DynamicStructuralModelofaWindTurbine12513SourcesofLoadsonaWindTurbine13914WindSimulation14715Fatigue15716FinalRemarks162AppendixA:BasicEquationsinFluidMechanics167AppendixB:Symbols171Index1753212J&JAerodynamicTurbines16/11/079:49AMPagevListofFiguresandTablesFigures1.1Horizontal-axiswindturbine(HAWT)41.2Machinelayout62.1Schematicviewofstreamlinespastanairfoil72.2Definitionofliftanddrag82.3Explanationofthegenerationoflift92.4PolarfortheFX67-K-170airfoil112.5Differentstallbehaviour122.6Computedstreamlinesforanglesofattackof5°and15°122.7Viscousboundarylayeratthewallofanairfoil142.8Schematicviewoftheshapeoftheboundarylayerforafavourableandanadversepressuregradient142.9Schematicviewofthetransitionalprocess153.1Streamlinesflowingoverandunderawing183.2Velocityvectorsseenfrombehindawing193.3Asimplifiedmodelofthevortexsystemonawing203.4Morerealisticvortexsystemonawing203.5InducedvelocityfromavortexlineofstrengthΓ213.6TheeffectiveangleofattackforasectioninawingandtheresultingforceR,liftLandinduceddragDi223.7Computedlimitingstreamlinesonastallregulatedwindturbinebladeatamoderatelyhighwindspeed233.8Rotorofathree-bladedwindturbinewithrotorradiusR243.9Radialcutinawindturbinerotorshowingairfoilsatr/R243.10Schematicdrawingofthevortexsystembehindawindturbine254.1Illustrationofthestreamlinespasttherotorandtheaxialvelocityandpressureup-anddownstreamoftherotor284.2Circularcontrolvolumearoundawindturbine294.3Alternativecontrolvolumearoundawindturbine303212J&JAerodynamicTurbines15/11/071:42PMPagevi4.4ThepowerandthrustcoefficientsCpandCTasafunctionoftheaxialinductionfactoraforanidealhorizontal-axiswindturbine324.5ThemeasuredthrustcoefficientCTasafunctionoftheaxialinductionfactoraandthecorrespondingrotorstates334.6Theexpansionofthewakeandthevelocityjumpinthewakeforthe1-Dmodelofanidealwindturbine344.7Schematicviewoftheturbulent-wakestateinducedbytheunstableshearflowattheedgeofthewake354.8Thevelocitytriangleforasectionoftherotor364.9Velocitytriangleshowingtheinducedvelocitiesforasectionoftheblade384.10Theefficiencyofanoptimumturbinewithrotation405.1Idealflowthroughawindturbineinadiffuser415.2Computedmassflowratioplottedagainstthecomputedpowercoefficientratioforabareandashroudedwindturbine,respectively435.3ComputedpowercoefficientforarotorinadiffuserasafunctionofthethrustcoefficientCT436.1ControlvolumeshapedasanannularelementtobeusedintheBEMmodel456.2Velocitiesattherotorplane476.3Thelocalloadsonablade486.4Alinearvariationoftheloadisassumedbetweentwodifferentradialpositionsriandri+1526.5DifferentexpressionsforthethrustcoefficientCTversustheaxialinductionfactora546.6Probabilityf(ViVoVi+1)thatthewindspeedliesbetweenViandVi+1andapowercurveinordertocomputetheannualenergyproductionforaspecificturbineonaspecificsite566.7Comparisonbetweencomputedandmeasuredpowercurve,i.e.mechanicalshaftpowerasafunctionofthewindspeed596.8PowercoefficientCpasafunctionofthetipspeedratio=R/Vo606.9PowercoefficientCpasafunctionoftheinversetipspeedratio–1=Vo/R606.10Sketchofapowercurveforapitchcontrolledwindturbine617.1Atypicaltorquecharacteristicforanasynchronousgenerator657.2Turnabletipusedasanaerodynamicbrakeandactivatedbythecentrifugalforce66Listoffiguresandtables|vii3212J&JAerodynamicTurbines15/11/071:42PMPagevii7.3Startingastallregulatedwindturbineathigh