风力机叶片挥舞振动特性分析

Flap Vibration Characteristics of Wind Turbine Blades

基于Hamilton原理建立了叶片小挠度挥舞振动模型,以及轴向拉伸和横向弯曲耦合的大挠度挥舞振动模型。根据这两个模型,采用假设模态法计算了叶片挥舞振动的固有频率,分析了转速和锥角对固有频率的影响,并比较了这两个模型下挥舞特性的差异,得到如下结论:1)叶片挥舞振动固有频率随转速增加而增大,转速对频率影响显著;2)固有频率关于零锥角对称,随锥角绝对值的增大而减小,锥角对频率的影响随转速的增加而愈加显著。

Based on the Hamiltonian principle,the simple model of a wind turbine blade with small flap deflection is established;another model of the blade with coupled axial-lateral bending is derived when large deflection is considered.By using the assumed modes method and according to these two models,the natural frequencies are calculated.Influences of the rotational speed and the pitch angle to vibration characteristics are discussed.Vibration characteristics derived from the two models are compared.The study indicates that： 1） the natural frequencies of the flap vibration increase with increasing of the rotational speed;the influence of the rotational speed is clear;2） the natural frequencies are symmetric about zero pitch angle,and decrease with increasing of the absolute value of the pitch angle;the impact of the pitch angle to frequencies becomes obvious with rising of the rotational speed.