风切变下塔影效应对大型水平轴风力机气动性能的影响

Effect of tower shadow effect on aerodynamic performance of large horizontal-axis wind turbine under wind shear

以NH1500三叶片上风向型水平轴风力机为研究对象,基于CFD方法分析了风剪切来流下塔影效应对风力机叶片与风轮的气动载荷、空间流场的影响.结果表明:对于风剪切条件下有/无塔架的2种模型,叶片表面压力分布的差异主要体现在前缘和吸力面;在1个旋转周期内,有塔模型的载荷波动幅值大于无塔的风轮模型,风轮的载荷波动幅值相对于单支叶片的较小;方位角150°~210°的时域为塔架模型的塔影中心区;塔影效应是导致风力机输出功率周期性波动的主要因素;塔架模型在叶片相位角180°时刻较无塔的风轮模型流场结构更为复杂;当叶片经过塔架时,流动分离点发生偏移,引起塔架两侧速度不对称.该研究结果为进一步研究塔影效应对风力机气动特性和空间流场的影响提供了一定参考.

Taking the wind rotor of NH1500 three-blade horizontal-axis wind turbine with the upwind direction as the research object,the aerodynamic load and the flow field of the wind turbine blade and the wind turbine under the condition of wind shear were analyzed based on CFD method.The results show that the difference of the pressure distribution on the blade surface between the two models with and without towers is mainly reflected in the front edge of the blade and on the suction surface under the condition of wind shear;in one rotation period,the amplitude of the load fluctuation of the tower model is larger than that of the no-tower model.Comparing with a single blade,the load fluctuation amplitude of the wind turbine is smaller,the time domain with the azimuth angle from 150°to 210°is the tower-image central area of the tower model,and the tower-image effect is the main factor leading to the periodic fluctuation of the output power of the wind turbine.The tower model is more complicated when the blade phase angle is 180°,and the flow field of the wind wheel model with no tower is more complex.When the blade passes through the tower,the flow separation point is offset,and the speed of the two sides of the tower is not symmetrical.The study provides a reference for further study of the effect of the tower shadow on the aerodynamic characteristics and the space flow field of the wind turbine.