不同入流条件及偏航角下的单风机尾流特性

Wake characteristics of single wind turbine under different inflow conditions and yaw angles

随着大型风电基地建设,上游风机在运行时会使下游风场风速下降,湍流度增大,造成下游风机发电功率降低,加剧风机的疲劳破坏并缩短其服役周期。因此,亟需开展风机尾流研究,明确其特性及演化规律。为了揭示不同入流及偏航角下的单风机尾流特性,基于单风机尾流风洞试验,验证基于大涡模拟(Large Eddy Simulation,LES)结合致动线模型(Actuator Line Model,ALM)数值模拟方法的准确性;基于LES-ALM模拟方法研究入流风场(包括风速及湍流度)及偏航角对风机尾流特性的影响,阐明正负偏航角下单风机尾流的对称性。结果表明:随着背景湍流度的增大,风机尾流恢复速度加快;当入流条件相同时,风机设置正负对称偏航角,其尾流风速也表现出一定的对称性;风机偏航角越大,风机尾流膨胀宽度会逐渐减小,并降低尾流风速的亏损程度。

With the rapid construction of large-scale wind farms,the upstream wind turbine will deteriorate the wind velocity in the wind turbine wake region and increase the wake turbulence,thereby reducing the power efficiency of the downstream wind turbine and aggravating the fatigue damage of the wind turbine to shorten its service life.Therefore,it is urgent to carry out the study of wind turbine wake characteristics.The main purpose of this study is to reveal the wake characteristics of a standalone wind turbine under different upstream flow conditions and with various yaw angles.Firstly,the accuracy of Large Eddy Simulation(LES)combined with Actuator Line Model(ALM)was verified by the corresponding wind tunnel test.And then,based on the LESALM simulation method,the effects of inlet(including velocity and turbulence intensity)and yaw angle on the turbine wake characteristics were studied,and the symmetry of the horizontal profiles of the wind turbine wake at the hub height was clarified with positive and negative yaw angles.The results show that with the increase of the background turbulence intensity,the recovery of the wind turbine wake will be accelerated.Moreover,under the same upstream flow conditions and symmetrical yaw angle,the certain symmetry of wind turbine wake velocity was also identified.When the yaw angle of the wind turbine increases,both the expansion rate of the turbine wake width and the deficit degree of the wake wind velocity would decrease.