风力机三维尾流模型的提出与校核

PROPOSALAND VALIDATION OFANEW 3DWAKE MODEL FOR WIND TURBINE

针对大型风力机叶轮范围内风剪切效应突出以及当前工程尾流模型局限于二维空间而忽略垂直方向风速变化的问题,该文综合考虑风速和湍流强度切变效应对尾流的影响,在前期所发展的二维2D_K Jensen尾流模型的基础上,提出一种新型三维尾流模型。之后,新模型被应用于多种工况条件、多种类型的风力机尾流计算中,较为全面地验证其精度及适用性。通过与外场实测和其他高精度数值模拟的结果进行对比,表明新模型对流向、横风向和垂直向的尾流速度均具有良好的预测精度,将来可应用于大型风电场发电量评估和微观选址工作。

With the increased size and power capacity of wind turbines,the impact of wind shear and turbulence intensity become increasingly relevant.However,the existing engineering wake models are limited to two-dimensional space and ignore the vertical wind shear and turbulence shear of incoming wind flow.To resolve this problem,taking into account both the wind shear and turbulence shear,a new three-dimensional wake model is proposed on the basis of the 2D_K Jensen model.Then,the performance of this newlydeveloped wake model is assessed through two types of wind turbine under different inflow conditions.The obtained results are compared with field measurements as well as the results of an advanced CFD method(LES,large eddy simulation).From the comparisons,it is found that the proposed three-dimensional(3D)wake model gives a good prediction in terms of both shape and velocity amplitude of the wake deficit for all three directions,including along-wind direction,cross-wind direction and vertical direction,especially in the far wake.With simple form and good accuracy,it can be expected that the new 3D wake model will be applied in the layout optimization of large wind farms.