水平轴风力机塔筒近尾迹流场PIV实验研究

摘要

应用PIV粒子图像测速技术,在风洞中测量水平轴风力机模型塔筒的近尾迹流场.通过对模型风力机在不同运行尖速比下、不同叶高平面内的塔筒近尾迹速度场和涡量场的分析,得到了塔筒近尾迹流场的结构特征,为水平轴风力机气动设计、性能预测及CFD数值模拟提供了依据.实验结果表明,受到风轮旋转效应的影响,在水平轴风力机塔筒下游轴向距离6倍当地弦长范围内,近尾迹在水平面内向一侧明显偏转,近尾迹流场相对塔筒中心轴面呈非对称分布.随着尖速比的减小,塔筒下游轴向距离6倍当地弦长范围内,近尾迹涡流宽度逐渐增大,且尾迹向一侧偏转的程度也越大.风力机叶片对塔筒近尾迹涡流的影响,在叶根部位高度平面内尤为显著,随着叶片高度的增加,叶片对塔筒近尾迹涡流的影响逐渐减弱.%In a wind tunnel, the near-wake velocity field behind the tower of a model horizontal-axis wind turbine (HAWT)was measured with particle image velocimetry (PIV)system. Near wake structure characteristics of tower were obtained by analyzing the data of velocity field and vorticity field at five tip speed ratios and at three blade spans. These data can be used to aid the accurate aerodynamic design and prediction of the performance of HAWT or serve as a benchmark for validation of CFD results. The experimental results show that the near wake flow of tower deflects to one side in six local chord lenth downstream due to the rotation effect of rotor, which leads to the asymmetric distribution of the near wake flow field about the central plane of tower. In six local chord lenth downstream of tower,the width of near wake vortex flow of tower increases gradually and its deflection to one side is also larger with decreasing of tip speed ratio. The influence of wind turbine blades on near wake vortex flow of tower is especially significant at blade root and this influence becomes weaker with increasing the blade span.