基于非线性气弹耦合模型的风力机柔性叶片随机响应分析

摘要

为准确模拟柔性叶片在紊流风速下的气弹响应，研究叶片振动对气动载荷与气弹响应的反馈，构建包含多体系统动力学模型与气动模型的柔性叶片非线性气动弹性力学模型。在将细长柔性叶片离散为多刚体系统基础上，运用计算多体系统动力学理论和 Roberson-Wittenburg 的建模方法，结合叶素动量理论，采用 Kaimal 模型模拟脉动风速，建立风力机柔性叶片的气弹耦合方程。算例以美国可再生能源实验室（NREL）研制的5 MW 近海风力机为研究对象，分析叶片的振动和叶根的挥舞与摆振力矩，研究柔性叶片振动对气动载荷影响。结果表明，叶片达到一定长度后，模拟风力机气弹响应问题时，其振动影响不可忽略。%In order to exactly model the aeroelastic response of a blade under turbulent flow and study blade vibration's feedback on aerodynamic load and aeroelastic response,here a nonlinear aeroelastic mechanical model containing flexible blade multibody system's dynamic model and an aerodynamic model was constructed.Through discreting a flexible slender blade into a multi-rigid-body system,the aeroelastic coupled equations of the blade were obtained by using the theory of computational dynamics of multibody system and Roberson-Wittenburg modeling method. In the coupled equations,the blade element-momentum theory (BEM)was used to calculate the aeroelastic load of the wind turbine blade and Kaimal model was used to calculate random wind speed.The time domain response of a 5 -MW offshore wind turbine blade of the US.Renewable Energy Laboratory was calculated.The response included the vibration of the blade and the flapwise and edgewise bending moments at the blade root.The effect of the vibration of the flexible blade on the aerodynamic load was also studied.The results revealed that the effect of slender blade vibration can not be ignored when simulating the aeroelastic response of a wind turbine.