漂浮式风力机在纵摇运动下的气动性能数值研究

Numerical study of aerodynamic performance of a floating offshore wind turbine under pitch motion

与固定式风力机不同,漂浮式风力机气动性能受六自由度平台运动影响。其中,平台纵摇运动的影响尤为重要。本文基于计算流体力学(CFD)方法,使用IDDES模型和重叠网格技术,研究漂浮式风力机气动性能在纵摇运动影响下的特性。使用实验数据验证数值模型,对漂浮式风力机在纵摇运动影响下的气动响应和周围流场实施数值模拟。结果表明,漂浮式风力机气动响应与平台纵摇运动同周期变化,且叶轮推力、扭矩的幅值以及平均功率随纵摇运动振幅增加而增大,随纵摇运动周期增加而减小。此外,发现漂浮式风力机在纵摇运动中的动态失速和尾涡干扰现象。漂浮式风力机的纵摇运动将对其气动性能产生较大影响,因此应在设计阶段予以考虑。

The aerodynamic performance of floating offshore wind turbines(FOWTs)is influenced by the 6 degrees of freedom(DOFs)platform motion,which is different from that of wind turbines with fixed foundations.Among these DOFs,the pitch motion is the most important.In this paper,the aerodynamic performance of a scale model wind turbine affected by the pitch motion is investigated using the computational fluid dynamics(CFD)method with the improved delayed detached eddy simulation(IDDES)model and overmesh technique.First,the numerical model is validated by the available experimental data.Then,the aerodynamic performance with the flow information around the rotor and in the wake is simulated.It is shown that the rotor thrust and torque varies with the harmonic pitch motion,whose amplitudes increase with the increment of the pitch motion’s amplitude and with the decrement of the pitch motion’s period.So does the average rotor power.Also,the dynamic stall and wake interference phenomena are found.Hence,the pitch motion may affect aerodynamics of FOWTs significantly,which should be considered in design procedure.