水平轴风力机近尾迹流场结构的实验研究

EXPERIMENTAL INVESTIGATION ON NEAR WAKE STRUCTURE OF HORIZONGTAL AXIS WIND TURBINE

在风洞开口实验段,应用PIV锁相周期采样技术测试风力机近尾迹速度场,通过分析速度场和涡量场,得到近尾迹流场结构特征。近尾迹中存在具有形态特征强烈的叶尖涡结构向下游不断传播。由风轮旋转轴向外,近尾迹的结构组成依次为中央尾迹区、叶尖涡诱导效应区和外部主流区。在叶尖涡诱导效应区内,涡流诱导效应使流场中存在明显的速度增益区和速度亏损区,且增益区和亏损区关于叶尖涡核中心对称。在研究区域内,叶尖涡向下游运动的轴向位移与尖速比成反比,径向位移与尖速比成正比,使叶尖涡诱导效应区影响范围随尖速比的增加径向扩展、轴向缩小。

The measure of velocity field in near wake of horizontal axis wind turbine （HAWT） was carried out using cross correlation particle image velocimetry （PIV） and axis-coder positioning period sampling system at wind tunnel opening. Near wake structure characteristics were obtained by analyzing velocity and vorticity at six tip speed ratios. Obviously, there were tip vortexes with forceful morphological character spreading to the downstream. Along the radial direction, near wake consists of central wake region, tip vortex inducing region and external mainstream region. In tip vortex inducing region, there were apparent profit areas and deficit areas of velocity, the profit area and the deficit area were symmetric with respect to the center of tip vortex core. In research district, tip vortex＇ s axial displacement was inversely proportional to tip speed rate, and its radial displacement was proportional to tip speed rate, this makes the tip vortex inducing region increase in radial area and decrease in axial area with the increase of tip speed rate.