径向网格数量对风力机数值仿真中径向流动的影响

INFLUENCE OF RADIAL GRIDS NUMBER ON RADIAL FLOW SIMULATION OF WIND TURBINE BLADES

为了探究风力机径向网格节点数量等关键参数对叶片径向流动特性的影响,使用稳态雷诺平均NS方程和两方程k-ωSST湍流模型,对MEXICO实验风力机进行仿真,分析弦向、径向网格节点数量以及出口距离的延伸、旋转域的扩大对叶片受力以及径向流动的影响。与实验结果对比发现:径向网格节点数量对三维分离流动至关重要,径向120个节点才能基本模拟出叶片上的三维气体分离流动。在径向网格节点数量过少时,即使弦向网格节点数量增至200也会产生较大误差;在弦向0.4C附近产生怪异的径向流线簇,进而导致压力分布、气动力分布预测的误差增大。在径向网格节点数量充足时,弦向100个节点也能满足受力分析的基本要求。

In order to explore the influence of key parameters such as the number of radial grids on radial flow simulation,the steadystate RANS equation and the two-equation k-ωSST turbulence model were adopted to simulate the MEXICO experimental wind turbine.The influence of chord-wise grids number,radial grids number,the extension of the exit boundary and the expansion of the rotation domain were analyzed and compared with the experimental results.It is found that the number of radial grids is very important for the 3D separation flow,and only up to 120 radial grids can the 3 D separation flow be simulated on the blade.With insufficient radial grids,large errors appear even there are 200 chord-wise grids on the blade surface.There are strange radial flow on blade surface near 0.4 C chord-wise position,which leads to the large errors of pressure distribution and aerodynamic force distribution.Nevertheless,even 100 chord-wise grids could satisfy the need of force simulation as long as sufficient radial grids are used.