基于大涡模拟的大型风力机在剪切来流条件下的尾流研究

Study on the wake of large wind turbines under shear flow conditions based on large eddy simulation

来流条件对大型风力机尾流特性影响重大,由于地面摩擦导致来流风在竖直方向有速度差异进而形成剪切风。为研究剪切来流风带来尾流特性变化,采用5 MW风力机作为研究对象,两台大型风力机串列的布置方式,基于大涡模拟(LES),模拟大型风力机不同间距在剪切来流风下尾流特性变化。结果表明:剪切来流风经过风力机,随着串列间距增大,对下游风力机风压扰动减小;且不同间距下,共同特点是轮毂处风压比其他地方更大,轮毂后风速损失较叶轮其他位置更加严重;不同间距工况下,尾流速度恢复处在5D工况相较于所有工况恢复距离最远,甚至在10D处之后才恢复,而8D工况时,在下游9D处恢复,11D工况时,在下游6D处恢复,说明间距越大,尾流速度恢复处位置越近。

The incoming flow condition has a great influence on the wake characteristics of large wind turbine.Due to the ground friction,the velocity difference of the incoming wind in the vertical direction leads to the shear wind.In order to study the change of wake characteristics caused by shear inflow wind,5 MW wind turbine was used as the research object.Based on large eddy simulation(LES),the wake characteristics of large wind turbine with different spacing under shear inflow wind were simulated.The results show that the shear inflow wind passes through the wind turbine,and the wind pressure disturbance on the downstream wind turbine decreases with the increase of the tandem spacing.Under different spacing,the common feature is that the wind pressure at the hub is larger than that at other locations,and the wind speed loss behind the hub is more serious than that at other locations of the impeller.Under different spacing conditions,the recovery distance of wake velocity at 5D condition is the farthest compared with all conditions,and it is not recovered until 10D.Under 8D condition,it is recovered at 9D downstream,and under 11D condition,it is recovered at 6D downstream,indicating that the larger the spacing is,the closer the position of wake velocity recovery is.