湖北丘陵山区不同气象条件对风机叶片覆冰特征影响的模拟分析

Simulation Analysis of the Impact of Different Meteorological Conditions on Wind Turbine Blade Icing Characteristics in the Hilly Regions of Hubei

摘要:

寒冷山区风能资源丰富，风力机在此区域下易发生叶片覆冰，本文根据湖北界山风电场覆冰观测记录，分析了风机叶片覆冰情况随2分钟平均风速的变化，结合叶片动态参数和叶素动量理论，采用欧拉法结合Fluent计算空气、水滴二相流，分析不同气象条件对水滴碰撞系数、覆冰厚度、结冰形状的影响，可简化计算过程，结果表明：水滴撞击位置主要分布在翼型前缘，在5°~25°的攻角范围内，随攻角的增大，水滴碰撞中心位置向下缘方向移动，覆冰厚度计算结果也反映了相同规律；在30~50 μm的水滴中值直径范围内，随中值直径的增加，水滴碰撞中心位置基本不变，水滴碰撞系数峰值和结冰厚度均增加；空气中液态水含量对碰撞特性的影响较小；随风速的增大，水滴碰撞峰值和碰撞范围增大，叶片覆冰厚度也随之增加，同时分析了界山风电场实测数据及相关文献中提到的风速大于某一阈值时，风机叶片覆冰概率降低的原因; 在-5 ℃~ -1 ℃温度范围内，随温度降低冰厚升高，同时冰厚的增幅先增大后减小，最后呈现稳定趋势，这主要是由于温度对叶片冻结系数的影响。

Abstract:

Wind energy resources are abundant in cold mountainous areas, but wind turbine blades are prone to ice in this area. An analysis of blade icing variation with the 2-minute average wind speed was conducted based on the ice observation records of the Jieshan wind farm in Hubei Province. Utilizing the blade element momentum theory and the FLUENT Eulerian model, water droplet collisions and icing behavior on wind turbine blades was investigated under various meteorological conditions. The findings indicate: water droplet collision position is mainly distributed in the leading edge of airfoil. Within attack angle ranging form 5° to 25°, the center position of water droplet collision moves to lower edge with attack angle increasing, and calculated ice thickness also reflects this pattern. Within a range form 30μm to 50μm of droplet median diameter, the position of droplet collision center remains essentially unchanged as median diameter increases, while both peak droplet collision coefficient and icing thickness increase. The liquid water content in the air has a minor impact on the collision characteristics. As the wind speed increases, both the peak droplet collision coefficient and the collision range increase, leading to a corresponding increase in the ice thickness on the blades. Additionally, the reasons for the reduced probability of ice accumulation on wind turbine blades when the wind speed exceeds a certain threshold, based on data from the Jieshan Wind Farm, are analyzed. Within the temperature range of -5°C to -1°C, as the temperature decreases, the ice thickness increases. Meanwhile, the rate of increase in ice thickness first accelerates, then slows down, and eventually stabilizes. This is mainly due to the influence of temperature on the freezing coefficient of the blades.