偏航条件下大型风机的流固耦合分析

Fluid-structure interaction analysis of a large wind turbine under yaw condition

流固耦合条件下叶片变形和振动的分析对于大型叶片的安全至关重要。基于叶素动量理论和Euler-Bernoulli梁的有限元建立大型风机双向流固耦合数值模型,用偏航修正、叶尖轮毂的非定常叶素动量理论计算风力机的气动载荷;通过2结点12自由度空间梁单元作为结构动力分析的基本模型,结合两套理论建立可以快速分析风力机叶片流固耦合作用下的输出特性和振动特性。通过对NREL 5 MW大型风力机计算的对比和分析,验证了方法的可行性并得到在流固耦合作用下风力机输出特性曲线和叶片结构变形。证明在风力机叶轮工作状态叶片发生振动,而且在偏航情况下,叶轮的功率输出和推力输出产生周期性波动。

The analysis on the blade deformation and vibration of a large wind turbine is of great significance to the safety of a large blade. In the paper,a mathematical model for the bidirectional fluid-structure interaction（ FSI） of a large wind turbine was established on the basis of blade element momentum theory（ BEMT） and finite element theory of Euler-Bernoulli beam,the non-constant BEMT containing yaw amendment and tip hub was used to calculate the aerodynamic load of wind turbine; 2-node 12-DOF Euler beam element was used for the dynamic analysis of structure,and a new method was established by combining the two theories to quickly analyze the output characteristics and vibration characteristics of the blade of a wind turbine under the action of FSI. Through analyzing the calculation of NREL 5 MW large wind turbine,the feasibility of the method was verified and the output characteristic curve of wind turbine and the deformation of blade structure were obtained under the condition of fluid structure interaction. It proves that vibration occurs when the wind turbine lies in operatingstates. In addition,under yaw condition,the power output and thrust output of a turbine will lead to periodic fluctuation.