大型风力机柔性叶片在运行工况下的内力分析

Internal Force Analysis of Flexible Blade of Large Wind Turbine Under Working Condition

为了准确地模拟柔性叶片在运行工况下叶片危险截面的内力,进行叶片的强度与刚度分析,并考察叶片的振动对气动载荷与气弹响应的反馈,以美国可再生能源实验室(NREL)发布的5 MW近海风力机为研究对象,建立了包含气动模型和系统的动力响应模型两部分的柔性叶片非线性气动弹性力学模型。采用计算多体系统动力学理论,基于Roberson-Wittenburg建模方法,结合叶素动量理论,建立了柔性叶片的气弹耦合方程,实现了叶片的气弹耦合时域响应分析。算例计算了NREL的5 MW近海风力机在紊流风速作用下,叶片各截面的挥舞、摆振和扭转方向内力矩的时域响应。研究成果对于叶片强度与刚度校核与优化设计有重要的应用价值。

In order to accurately model the internal force of dangerous sections of flexible blade under working condition,the strength and stiffness of blade are analyzed,and the blade vibration＇s feedback on aerodynamic load and aeroelastic response is researched. Taking the 5MW offshore wind turbine announced by American NREL as study object,the flexible blade＇s nonlinear aeroelastic force model which contains aerodynamic model and dynamic response model of whole system is established. This paper uses the dynamics theory of computational multi-body system,based on Roberson-Wittenburg modeling method,combined with Blade Element-Momentum Theory（BEM） to establish the aeroelastic coupling equations of flexible blade and realize the time-domain response analysis of aeroelastic coupling of blade. On the foundation of 5MW offshore wind turbine of NREL under a random wind speed,the time-domain responses of brandish,shimmy and torsional moments acted on each section of blade are calculated. The results have important application value for proofreading the strength and stiffness of blade and blade optimization design.