漂浮式风电机组平台运动对叶片应力特性的影响

Influence of Floating Wind Turbine Platform Motion on Blade Stress Characteristics

海上风电机组运行时,受波浪和风载影响,在平台运动下叶片的气动和结构载荷较为复杂。采用CFD方法对NREL 5MW风电机组进行了非定常气动性能数值模拟,然后加载至叶片固体模型进行形变量分析与应力分布研究。研究结果表明:展向80%至90%的叶片段承担了叶片整体最大做功量。平台运动下叶片整体形变量变化较大,耦合运动所对应的风电机组叶片在前向与后向运动时叶尖位移量差异较大,会显著增加叶片展向载荷波动。平台运动下,压力面中叶段出现应力集中。海上风、浪等载荷引起的平台多自由度运动,会使扭矩输出降低,叶片变形与压力载荷幅值增大。中叶段40%~70%内应力集中程度较为严重且随相位角变化急剧,所以需要对叶片中部应力集中部分进行材料或者结构强化。

With the effect of wave and wind loads,the aerodynamic and structural loads of floating offshore wind turbine blades are complex induced by platform motion.The unsteady aerodynamic performance of NREL 5MW wind turbine is simulated by CFD method and then loaded into the blade solid model to analyze the deformation and stress distribution.The results show that 80%to 90%span takes the most torque of the blade.The overall deformation of the blade changes significantly under the platform motion.The tip displacement of the blade corresponding to the coupled motion has a significant difference between forward and backward motion,substantially increasing the spanwise load fluctuation.Under the platform motion,stress concentration occurs in the middle spanwise of the pressure surface.The multi-degree motion of the platform caused by wind and wave loads will reduce the torque output,increasing the blade deformation and pressure load amplitude.The stress concentration of 40%~70%in the middle blade is serious.It changes rapidly,so it is necessary to strengthen the material or structure of the stress concentration part in the middle of the blade.