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对NACA4412翼型流场进行了数值模拟,发现在翼型尾部上表面存在一对方向相反交替脱落的漩涡.为了改善叶片的空气动力特性,在叶型尾部加装Gurney襟翼,并进一步改进为钝尾缘的叶型.研究结果表明:钝尾缘翼型尾部漩涡消失,升力系数增大,且在翼型失速前升力系数增大较为明显,阻力系数稍有增加,气动性能明显好于原翼型.基于改进前后翼型对风力机桨叶进行了优化设计,分析比较了两种翼型风力机的功率输出特性.结论:在相同功率下,具有钝尾缘翼型的风力机桨叶弦长相对较小,桨叶的扭角相近;在风力机工作风速范围内,改进翼型的风力机功率和功率系数都有所增加,尤其是在低风速段提高较明显,启动风速功率增量达到了30.5%;钝尾缘翼型风力机性能明显优于原翼型的风力机,年输出功率提高了7.69%.
Numerical simulations of the NACA 4412 airfoil flow field show that there is a pair of vortex shedding alternately on the upper surface of the tail of the airfoil.In order to improve the aerodynamic characteristics of the blade, Gurney flaps are added to the tail of the airfoil and further improved to Blunt trailing edge.The results show that the tail vortex at the blunt trailing edge disappears and the lift coefficient increases, and the lift coefficient increases more obviously before the airfoil stalls, the drag coefficient increases slightly, and the aerodynamic performance is obviously better than the original Airfoil.Based on the improved front and rear airfoils, the wind turbine blades are optimized, and the power output characteristics of the two airfoils are analyzed and compared.Conclusion: At the same power, the wind turbine blade with a blunt trailing edge airfoil The chord length is relatively small and the torsional angle of blades is similar. In the operating wind speed range of wind turbine, both the power and the wind power factor of the improved airfoil increase, especially when the wind speed increases obviously, The output of the blunt-ended airfoil wind turbine is obviously superior to that of the original airfoil, and the annual output power is increased by 7.69%.