基于自由尾迹方法的自转旋翼气动特性研究

为研究自转旋翼的气动特性,建立了自转旋翼的自由尾迹方法计算模型,并耦合桨叶挥舞运动模型和自转旋翼配平模型,建立了一种分析自转旋翼气动特性的方法。以某试验自转旋翼为算例对该方法进行了验证并运用该方法研究了自转旋翼的尾迹几何形状和桨盘诱导入流分布特性。研究结果表明:建立的自由尾迹方法计算模型可以满足自转旋翼气动特性分析的需求,相比传统的近似入流模型,该自由尾迹方法模型精度更高;前飞时自转旋翼尾迹随时间推移自桨盘处向桨盘后上方运动,水平面内自转旋翼尾迹畸变略小于驱转旋翼;自转旋翼桨盘诱导入流呈非均匀分布,从桨盘前缘到后缘,下洗入流大致呈不断增加趋势,在相同拉力水平下,自转旋翼90°方位角附近及桨盘后缘的诱导入流小于驱转旋翼。

Investigation of autorotating rotor aerodynamic characteristics based on free wake method

To investigate autorotating rotor aerodynamic characteristics, a free wake method calculation model which couples blade flapping motion model and trim model of autorotating rotor is established in this paper, and an analysis method for autorotating rotor aerodynamic characteristics is established. Then, this method is verified by a test example of an autorotating rotor based on the method. Lastly, wake geometry and rotor disk induced inflow distribution characteristics of autorotating rotor are investigated by the method. The results indicate that the free wake method calculation model established in this paper can meet the requirement of autorotating rotor aerodynamic characteristics analysis and the model accuracy is higher compared with the traditional approximate inflow model. Autorotating rotor wake moves upward and backward from the rotor disk as time goes on in the forward flight. The distortion of autorotating rotor wake is slightly smaller than powered rotor in the horizontal plane. The distribution of autorotating rotor disk induced inflow is nonuniform. Downwash inflow generally increases gradually from the leading edge to the trailing edge of the rotor disk. Autorotating rotor induced inflow is less than powered rotor near 90° azimuth and at the trailing edge of the rotor disk at the same thrust.