桨叶尖削对高空无人机气动性能影响

螺旋桨在临近空间高速运转时，由于工作环境大气物理特性，桨尖区域受空气压缩性影响严重，使螺旋桨气动性能降低。为了改善高空螺旋桨的高速性能，将翼尖修形的思想应用于高空无人机螺旋桨上，分别对螺旋桨桨尖区域进行不同角度的尖削。计算模型应用多参考系模型和周期性边界条件，对不同尖削桨叶运行状态进行模拟并对桨叶气动性能进行计算，根据计算结果分析桨叶尖削对螺旋桨气动性能的影响。研究结果表明：对螺旋桨桨尖区域进行尖削，可以减缓桨尖空气压缩性影响，减小桨尖阻力，进而提升螺旋桨气动性能，且当尖削角度α=70°时，螺旋桨的高速性能最佳，其气动效率相比与原始桨叶提升约5%。

Influence of Propeller Taper on Aerodynamic Performance of High-altitude Unmanned Aerial Vehicles

The aerodynamic performance of the propeller running at high speed is reduced due to the compressibility of the air in the tip area. In order to improve the high-speed performance of the high-altitude propeller, the idea of wing tip modification is applied to the high-altitude unmanned aerial vehicles (UAVs) propeller, and the propeller tip area is sharpened at different angles. The multi-reference frame model and periodic boundary conditions were used to simulate the operating states of different taper blades and calculate the aerodynamic performance of blades, analyze the influence of the blade tip cutting angle on the aerodynamic performance of the blade based on the calculation result. The research results show that the effect of blade tip air compressibility can be alleviated by blade tip sharpening, and the blade tip resistance can be reduced, thus the aerodynamic performance of the propeller can be improved. At the cutting angle of 70°, the high speed performance is about 5% compared with the original blade.