基于叶素理论风轮气动性能计算预测精度研究

RESEARCH ON PREDICTION ACCURACY OF WIND TURBINE ROTOR'S AERODYNAMIC PERFORMANCE CALCULATION BASED ON BLADE ELEMENT THEORY

为研究壁面处网格正交性对数值计算结果的影响,推导出壁面附近流动参数一阶导数离散误差与网格线交角的数学关系,采用N-S方程方法分别对多种壁面处网格线交角的平板紊流附面层流动和翼型绕流进行计算分析。研究表明:壁面处网格正交性对附面层内速度分布计算预测精度和壁面摩擦阻力影响较大。对于基于叶素理论三维风轮气动性能计算,通过一模型风轮计算实例表明:在低叶尖速比时翼型升力系数计算精度对风轮性能预测精度影响较大,高叶尖速比时翼型阻力系数计算精度对风轮性能预测精度影响较大。

The turbulent boundary flow over a fiat plate and the flow around airfoil in various intersection angle of grid lines near the wall by using N-S equations method were calculate and analyzed. The results showed that the orthogonality of the grid which is near the wall has great effect in calculation prediction accuracy of boundary velocity distribution and the skin friction drag. For the three-dimensional aerodynamic performance calculation of the wind turbine rotor based on blade element theory, the calculation example of a model of rotor showed that the effect of calculation accuracy of the air- foil＇s lift coefficient to the prediction accuracy of the rotor＇s performance is great when there is a low blade top speed m- rio, and the effect of ealeulation aecumcy of the airfoil＇ s drag coefficient to the prediction accuracy of the rotor＇ s perfor- mance is great when there is a high blade top speed ratio.