半潜型垂直轴风机纵荡下气动载荷特性

Aerodynamic load characteristics of vertical axis semi-submerged floating wind turbine under surge motion

为了研究半潜式垂直轴浮式风机纵荡运动对风机气动载荷的影响,本文建立了5MW浮式风机、平台、系泊系统全非线性耦合的计算模型,采用流体固体交互方法和重叠网格技术对风浪双激励下平台纵荡运动时的风机气动载荷进行分析,研究了不同速比下纵荡运动对转矩系数、叶片推力系数、能量利用率的变化规律,并与相同速比下陆地垂直轴风机进行比较。结果表明:高速比下平台以较高纵荡均值做高频小幅振荡;回复运动时转矩系数大于正向运动时转矩系数;能量利用率系数在中低速比时大于陆地风机;叶片推力系数和转矩系数变化趋势相同。本文的研究结论对于分析浮式风力机叶片载荷和估算深远海风场年发电量具有理论指导意义。

A fully nonlinear coupled model with a 5MW floating wind turbine,semisubmersible platform,and mooring system was established for studying the aerodynamic characteristics of a semisubmersible vertical axis floating wind turbine under surge motion. The trends shown by the variation in torque,thrust force,and power utilization coefficients of the turbine during platform surge motion under the effect of regular waves and wind were studied through the dynamic fluid-body interaction and overset mesh method and compared with those of the vertical axis turbine on land under the same tip speed ratio. The main results show that high speed ratios are associated with high mean values of platform oscillation frequencies. The torque of the turbine is higher when the platform is moving back than that when the platform is moving forward. The energy utilization coefficient is larger at lower to middle TSRs compared with that of the on-land wind turbine. The changes in thrust force coefficient and torque coefficient follow the same trends. The conclusions of this research provide theoretical guidance to the analysis of the blade loads of floating wind turbines and the estimation of the annual power generation of offshore wind farms.