叶片数对尾缘加弯板垂直轴风力机功率影响数值模拟

为了探究叶片数量对叶片尾缘加装弯板直线翼垂直轴风力机气动特性的影响,通过不同叶片数量下直线翼叶片尾缘加弯板对垂直轴风力机叶片周围流场改善情况的对比,分析其气动特性变化.选取NACA0018直线翼型作为研究对象,利用数值模拟计算7种弯板长度下,2,3,4这3种叶片数量下的直线翼垂直轴风力机动态输出特性和静态起动特性.研究结果显示:该类升力型垂直轴风力机的气动特性受到叶片数量和弯板长度的综合影响,弯弦比的增加能够提升风力机的阻力性能,但会弱化因叶片数量增加导致风力机产生的功率系数的差别;在不同叶片数量下,适当弯板长度对风力机静态起动性能具有优化作用,但其起到优化作用的方位角不同,且2叶片时优化效果最佳,平均转矩系数提升40%.该研究为垂直轴风力机叶片尾缘的设计与优化提供依据.

Numerical simulation on effects of number of blades with plate added at blade trailing edge on torque coefficient of vertical axis wind turbine

In order to explore the influence of number of blades with plate added at the blade trailing edge on the aerodynamic characteristics of vertical axis wind turbine(VAWT), the torque coefficient of a VAWT with various numbers of blades was analyzed. The improvement in the flow field around the turbine blade was identified under different conditions of number of blades. The torque characteristics and static starting performance were calculated by numerical simulation for a SB-VAWT with seven curved plate lengths for 2, 3 and 4 blades based on a typical airfoil NACA0018, which has been often used in VAWTs. The simulated results showed that the aerodynamic characteristics of this lift-type VAWT were affected by the number of blades and the length of the curved plate. The increasing plate length can improve the performance of the wind turbine due to the drag, but could suppress the change in torque coefficient due to the increase of number of blades. Under the condition of different numbers of blades, the optimum curved plate length can optimize the static starting performance of the wind turbine. At different numbers of blades, a properly extended curved plate can optimize the static starting performance of the turbine, but the optimized performance occurs at different azimuth angles. Specially, the optimized performance is the best when the number of blades is 2, and the average torque coefficient is increased by 40%. This study has provided a basis for the design and optimization of blade trailing edge for VAWTs. 