基于面元法和FEM的海上浮式风力机叶片动力响应研究

DYNAMIC RESPONSE ANALYSIS OF FLOATING OFFSHORE WIND TURBINES BLADES BASED ON PANEL METHOD AND FINITE ELEMENT METHOD

考虑水动-气动耦合模型,研究海上浮式风力机在风浪作用下动力响应的数值模拟方法。采用速度势面元法求解浮式风力机叶片压力分布以及时变气动载荷;建立NREL 5 MW风力机的有限元模型,通过瞬态分析得到叶片的变形和应力分布。计算表明,在展长方向,越靠近叶根处,应力值越大;在弦长方向上,越靠近前缘点应力值越大。和风载荷单独作用相比,波浪载荷导致浮式平台产生较大幅度的纵荡和纵摇运动,能量传递到上部风力机后导致叶片的变形和应力更大。

Considering the hydro-aero coupled model,the numerical simulation algorithm on the dynamic response of floating offshore wind turbines(FOWTs)under environmental loading including wind and waves is established.The pressure distribution and time-varying aerodynamic loads on each blade are calculated with velocity-potential based panel method.Then the finite element model of NREL 5 MW wind turbine is established,and the blade deformation and stress distribution are obtained through the transient analysis.The results show that the von Mises stress is greater where the elements are closer to the root in the span direction,while the larger stress can be also observed near the leading edge in the chord direction.Comparing with the wind loads acting alone,the wave load will lead to the larger surge and pitch amplitudes.This amplified motion can transmit more energy to the upper wind turbines which will cause larger blade deformations and stresses.