三叶片直线翼垂直轴风力机非定常流场速度分析

垂直轴风力机在回转过程中，叶片尾流的相互干涉和叶片攻角变化，使垂直轴风力机周围流场异常复杂。为探明直线翼垂直轴风力机在二维流场中速度分布及风力机叶片迎风角度变化关系，在风洞试验中采用激光多普勒测速仪(Laser Doppler velocimetry，LDV)技术，对所设计的三叶片直线翼垂直轴风力机流场风速进行试验研究，获得了该风力机叶片周围流场的速度分布情况。在建立直线翼垂直轴风力机在不同转速下叶片迎风角度变化的数学模型基础上，应用仿真软件对被测风力机流场进行分析计算。通过数学模型得知，来流风速夹角随回转角的变化情况可用正弦函数近似表示, 并且随着叶尖速比的增大逐渐减小。风洞试验和CFD结果表明，风力机在回转过程中，叶片前缘场域有乱流生成，并且该域风速值偏大；而在叶片旋转内部以及下流区域内会形成一个宽大的低速区域，并且伴随叶尖速比的增加，低速区域具有扩大趋势。

Analysis on the Element Unsteady Flow Speed Field of Straight-bladed Vertical Axis Wind Turbine with Three Blades

The flow field around a vertical axis wind turbine is much complicated because the blades pass in non-uniform flow field by the blade wake and the variation with the azimuth angle of the blade’s angle of attack during rotation. To explore the relationship between the SB-VAWT and the attack angle of the wind turbine blades during rotating, and to clear the speed distribution and variation in quadratic element flow field, wind velocity in flow field around the straight-bladed vertical axis wind turbine with three blades is measured using laser Doppler velocimetry(LDV) technology, and velocity distribution relationship of flow field around wind turbine in different tip speed ratios are obtained in the wind tunnel test. Based on the established mathematical model of the blade movement at attack angle changes of the SB-VAWT in different values of azimuths, the velocity distribution relationship of flow field around wind turbine in the different tip speed ratios wis analyzed utilizing the movement analysis software.The following conclusions can be obtained：The turbulence is generated in the region of the blade leading edge, and the relative wind speed around the blade is larger; There is a wide low wind velocity field will appear from the wind turbine internal region to downstream area, along with increase of tip speed ratio, there is an expanding tendency of low wind velocity region.