风机叶片结冰对其一体化结构动态响应影响的数值分析

Numerical Analysis of Influence of Blade Icing on Dynamic Response of Integrated Wind Turbine Structure

基于美国可再生能源实验室的导管架式一体化海上风机模型,将计算流体力学(CFD)方法与风机一体化分析方法进行耦合,研究叶片结冰过程及其结冰后对风机整体动态性能的影响.首先将一体化分析得到的叶片运动姿态输入到CFD中,采用离散多相模型和融化-凝固模型进行三维风机叶片覆冰增长模拟,然后应用k-ε湍流模型计算结冰前后的气动性能,最后将叶片覆冰后的气动载荷结果返回到一体化分析方法中,分析叶片结冰对风机整体响应产生的影响.计算结果表明,叶片沿叶展方向结冰呈线性增加,结冰主要集中在叶片前缘,叶尖处积冰最厚;覆冰后叶片各剖面翼型升力系数降低、阻力系数升高.叶片结冰会降低整机功率、转子的转矩和转速,叶尖和塔顶产生额外振动响应,风机达到额定功率所需风速增大.

Based on the integrated jacket-support offshore wind turbine model of the National Renewable Energy Laboratory(NREL), the computational fluid dynamics(CFD) method is coupled with the wind turbine integrated analysis method to study the blade icing process and its influence on the overall dynamic performance of the wind turbine. First, the blade motion attitude calculated by the integrated analysis method is input into CFD. The discrete multiphase model and melting solidification model are used to simulate the icing growth of three-dimensional wind turbine blades. The k-ε turbulence model is used to calculate the aerodynamic performance before and after icing. Finally, the aerodynamic results after blade icing are returned to the integrated analysis method to analyze the influence of blade icing on the overall response of the wind turbine. The results show that the blade icing increases linearly along the blade span. The icing is mainly concentrated on the leading edge of the blade with the thickest ice accumulation at the tip. The lift coefficient decreases and the drag coefficient increases after icing. Blade icing will reduce the power of the whole machine, the torque, and the rotor speed. At the same time, it will lead to additional vibration response at the blade tip and tower top, and increase the wind speed required by the wind turbine to reach the rated power.