下击暴流作用下风力发电机表面风压特性

Wind Pressure Characteristics of Wind Turbine Surface Under Thunderstorm Downburst

为揭示下击暴流风场特性和风力机在风场作用下的风压特性,基于计算流体动力学(computational fluid dynamics,CFD)方法对下击暴流风场特性和风力机风压特性进行研究。通过与Wood半经验理论模型对比,验证数值模拟方法的正确性。从风速变化来看,地形对风场变化作用明显,平地下击暴流径向风速在近地面位置较大,随径向距离增加,风速先增大后减小。山地下击暴流主要作用于迎风坡和山顶位置,在背风坡形成绕流涡旋区域,背风坡风速较小,山体具有阻挡效应。迎风面山体坡度对风场有加速作用,最大风速位置为山顶近地面区域。以GW2.5MW风力发电机为例,研究风力发电机位于平地、山坡和山顶位置处的风压特性。结果表明:山顶处风机表面风压集中分布在距离地面0~25m区域内,山坡处风机表面最大风压主要分布在机舱底部,平地处风机表面最大风压集中分布在距离地面0~40m区域的塔筒表面。研究结果可以为风力发电机的设计及安全运行提供一定参考。

In order to reveal the characteristics of the downburst wind field and the wind pressure characteristics of the wind turbine under the action of the wind field, based on the computational fluid dynamics(CFD) method, the downburst wind field characteristics and the wind pressure characteristics of the wind turbine were studied. By comparing with the semi-empirical theory of Wood, the correctness of numerical simulation method was verified. From the perspective of wind speed changes, the topography has an obvious effect on the variations in the wind field. The radial wind speed of the flat ground turbulence is larger near the ground. With the increase of radial distance, the wind speed first increases and then decreases. The downburst current mainly acts on the windward slope and the hilltop position and forms a vortex area around the leeward slope. The downburst has a lower wind speed on the leeward slope, and the mountain has a blocking effect. The slope of the mountain on the windward side has an accelerating effect on the wind field, and the location of the highest wind speed is the area near the top of the mountain. Taking the GW2.5 MW wind turbine as an example, the wind pressure characteristics of the wind turbine on flat ground, hillside and mountain top were studied. The result shows that the maximum wind pressure on the surface of the wind turbine at the top of the mountain is concentrated in an area 0~25 m above the ground, the maximum wind pressure on the surface of the wind turbine on the hillside is mainly distributed at the bottom of the nacelle, and the maximum wind pressure on the surface of the wind turbine on the flat ground is concentrated in the area 0~40 m from the ground. The research results can provide valuable references for the design and safe operation of wind turbines.