低雷诺数旋翼翼型设计及气动仿真

研究了低雷诺数下薄圆弧旋翼的翼型,考虑其对高气动性能、高结构强度和便于制造和轻量化的要求,提出一种具有上凸结构的薄圆弧翼型。通过在翼型上表面增加凸起结构,增加部分弦长的翼型厚度并安装加强筋来提高翼型延展向的结构强度;设计出了最大厚度为4.3%、圆弧均匀厚度为2.5%、最大弯度为5.5%和均匀弯度为4.5%的薄圆弧翼型。采用基于二维定常、不可压缩Navier-Stoke方程的数值仿真方法计算了该翼型在雷诺数为40,000~100,000,迎角为-4°~12°下的气动性能,并获得了该翼型上下表面的压力系数分布线和速度矢量图。采用该翼型制作了直径为40cm,质量为15g,桨距为15.7cm的碳纤维旋翼;在悬停状态下完成了它的升力和结构强度试验。实验结果显示其性能满足使用要求。目前,研制的旋翼已成功地应用于某型多旋翼飞行器。

Design and aerodynamic simulation of low Reynolds number rotor airfoil

This research focuses on the thin circular arc rotor airfoils at a low Reynolds number. A novel thin circular arc airfoil with a convex structure was designed in consideration of its demand for high aerodynamic performance, high structural strength, lightweighting and easy manufacture. A convex curve on the upper surface of the airfoil was adopted to increase the thickness of airfoil at the partial chord and a stiffener in the airfoil was installed to improve the structural strength of blade span wise. The designed thin circular arc airfoil has the maximum thickness of 4.3%, a circular average thickness of 2.5%,the maximum camber of 5.5% and an average camber of 4.5%. Numerical simulations for computing the aerodynamic performance of the airfoil were performed at the representative Reynolds number between 40,000 and 100,000, and the angle of attack (AOA) from -4°to 12° by using the two dimensional steady and incompressible Navier-Stoke equations. The pressure coefficient distribution line of airfoil surfaces and the velocity vector were acquired. A carbon fiber rotor with a diameter of 40 cm, a mass of 15 g and rotor pitch of 15.7 cm was manufactured with the present airfoil, and the experiments on the lift force and the structural strength in a hover state were performed and the results show the performance of the airfoil meets the use requirments. At present, the developed rotor airfoil has been successfully used in a rotor aircraft.