周期艏摇运动对浮式风力机的气动影响

Aerodynamic Performance of Floating Wind Turbine under Periodic Yaw Motion

相比于偏航工况,浮式风力机在风波联合作用下的艏摇运动不仅改变了来流的入射角度,又给叶片附加了牵连角速度,对其气动特性及稳定性带来巨大的影响。基于升力面自由尾迹方法研究周期艏摇运动对NERL 5 MW浮式风力机的气动影响,从入流速度的角度分析艏摇运动的作用机制,捕捉到了艏摇运动下的畸变尾迹,评估了风轮-尾迹效应。结果表明:幅值为3°的周期艏摇运动下,风力机平均功率上升了1.49%,波动幅值接近100 kW,最低功率值等于3°偏航工况;充分发展的尾迹对风轮的诱导作用略有减小,但对特定叶片的诱导作用反而加强:初始时刻位于特定方位角的某叶片会持续过载,且整机的艏摇及横摇力矩波动剧烈,不利于风力机长时平稳运行。

Under the combined action of wind and waves,floating offshore wind turbines inevitably experience periodic yaw motion.Compared to steady yaw conditions,yaw motions not only change the incident angle of incoming flow,but also impose angular velocity to the airfoil,which has a huge impact on the aerodynamic characteristics and stability of floating wind turbine.In this paper,the lifting surface method combined with the free wake method was used to study the aerodynamic performance of floating wind turbine under periodic yaw motion.From the perspective of the inflow velocity,the mechanism of the yaw motion is analyzed.The distortion wake under the yaw motion is captured,and the rotor-wake effect is evaluated.Result shows that under 3°amplitude periodic yaw motion,floating wind turbine′s average power has increased by 1.49%,the amplitude is closed to 100 kW,and the minimum power is equal to 3°steady yaw condition.The average rotor-wake induce effect is slightly reduced,however,the effect on specific blade will enhance.A blade at a special azimuth at the initial moment will continue to be overloaded,and the yawing and rolling moment of the wind turbine will fluctuate sharply,which is not conducive to the long-term stable operation of the floating wind turbine.