双层翼叶片几何参数对水平轴风力机气动性能影响研究

为了提高风力机的气动性能，基于NREL Phase Ⅵ水平轴风力机叶片，设计出的一种双层翼叶片。通过计算流体力学的方法，在不同来流风速下，对比分析了双层翼叶片与按比例缩放各叶高处弦长的NREL Phase Ⅵ水平轴风力机叶片的扭矩与弯矩，研究了叶片实度的影响，发现实度增加并不是双层翼叶片的气动性能优于原始NREL Phase Ⅵ风力机叶片的主要原因。对不同弦长比、垂直距离及水平距离的大小叶片所组成的双层翼结构进行数值模拟研究，利用流线图着重分析了大小叶片水平距离对风力机气动性能的影响，总结了气动性能随双层翼叶片几何参数的变化规律，发现在15 m/s至25 m/s的风速下，选择较大弦长比、较大垂直距离或者较小水平距离的双层翼叶片可得到较高的扭矩值，但弯矩值也会随之增加。

Investigation on the Influence of Double-Wings Blade Geometric Parameters on the Aerodynamic Performance of Horizontal Axis Wind Turbine

In order to improve the aerodynamic performance of wind turbine, a double-wings blade based on the blade of NREL Phase Ⅵ horizontal axis wind turbine is studied. By the method of computational fluid dynamics, the comparison of torque and bending moment between NREL Phase Ⅵ wind turbine scaling blade and double-wings blade under the same conditions is made to analyze the influence of rotor solidity. The fact that the aerodynamic performance of double-wings blade is better than that of the original NREL Phase Ⅵ wind turbine blade is not caused by the increase in solidity. Furthermore, the numerical simulation of double-wings blades with different chord length ratios, vertical distances and horizontal distances is conducted and the influence of horizontal distance on the aerodynamic performance of wind turbine is analyzed emphatically by the velocity streamlines at different cross sections along the blade spanwise direction of double-wings wind turbine. Finally, the variation trend of aerodynamic performance with geometric parameters of double-wings blade is summarized. The results show that at the wind speeds of 15 m/s to 25 m/s, the double-wings blade with a larger chord length ratio, a larger vertical distance or a smaller horizontal distance can obtain a larger torque, but the bending moment will also increase accordingly.