1.5MW风力机塔架-基础的动力特性研究

采用多种计算模型结合敏感性分析,研究了塔架及塔架-基础的动力特性,发现塔架与基础的振动有一定的耦合作用;考虑基础与塔架相互作用后,塔架各阶自振频率降低,特别是高阶自振频率降低较多;在地震液化等极端工况下,地基基础对塔架动力特性的影响更明显。总结并分析了塔架的振源,指出脉动风荷载是风力机设计中必须重视的部分;风绕塔架流动一般处于超临界或跨临界范围,在超临界范围不会出现明显的塔架涡激振动,在跨临界范围可能出现严重的振动;风轮属细长弹性体、气动特征明显,其振动响应比较复杂且易发生破坏事故。为减小柔性塔架振幅,给出了风力机起动时快速跳过瞬态共振区、增加塔架阻尼和优化塔架体型以进一步改善塔架动力特性等方面的建议。

Study on dynamic characteristics of the ower-foundation of 1.5 MW wind turbine

The dynamic properties of the tower and tower-｜foundation were studied by using several different models with sensitivity analysis.It was concluded that the vibration of the tower interacted with that of foundation.The natural frequencies of the tower,especially the high-｜order natural vibration frequencies,decreased when the interaction was taken into account.The foundation had more significant impacts on the dynamic characteristics of the tower in extreme conditions,such as the liquefaction.The sources of the tower vibration were summarized and discussed,and results showed that fluctuating wind should be paid special attention to.Furthermore,the wind which flowed around the tower was generally under the super-｜critical or over-｜critical condition,and the tower did not appear obvious vortex-｜induced vibration under the super-｜critical condition.But serious vibration might occur under the over-｜critical condition.The rotor was slender and flexible with evident aerodynamic characteristics.Its vibratory response was complex and it was prone to be destroyed.In order to reduce the vibratory amplitude of the flexible tower,it was recommended that the wind turbines start quickly to skip transient resonance interval.Moreover,increasing the damping and optimizing the tower shape could also improve its dynamic characteristics.