In order to improve the aerodynamic performance of the ducted tail rotor, parametric investigations and optimization of the interior duct surface are performed based on the Computational Fluid Dynamics (CFD) method. Firstly, to predict the aerodynamic characteristics of the ducted tail rotor with high precision and efficiency, the Reynolds-Averaged Navier-Stokes (RANS) solver coupled with body-fitted mesh around rotor blade is established based on the rotating reference frame. Then, novel parametric researches on the aerodynamic characteristics of the ducted tail rotor are conducted with different lip radii, transition section lengths, and duct outlet areas respectively, and the flow separation mechanism on the different interior duct surfaces are obtained. Finally, a new curve lip shape parameterized by the Class Shape Transformation method is employed to replace the conventional circular lip, besides, the transition length and the outlet area which have great influences on the flow separation phenomenon are combined to conduct the optimization of the interior duct surface. Attribute to the suppression of the flow separation, the required power and the FM of the optimized ducted tail rotor show a maximum decrement of 2.49% and a maximum increment of 2.44% with respect to the baseline SA365N1 ducted tail rotor respectively.

为了提高风管尾旋翼的空气动力学性能，基于计算流体动力学（CFD）方法进行了参数研究和内部风道表面的优化。首先，为了高精度，高效地预测风管尾旋翼的空气动力学特性，基于旋转参考系，建立了雷诺平均纳维-斯托克斯（RANS）求解器，并在转子叶片周围建立了适合人体的网格。然后，分别针对不同的唇缘半径，过渡段长度和风管出口面积，对风管尾旋翼的空气动力学特性进行了新颖的参数研究，并获得了在不同风管内表面上的分流机理。最后，用类形状变换法参数化的新型曲线唇形代替传统的圆形唇形，并结合对流分离现象有较大影响的过渡长度和出口面积来进行内风道表面的优化。归因于流分离的抑制，相对于基准SA365N1导管式尾旋翼，优化的导管式尾旋翼的所需功率和FM分别显示出最大减量2.49％和最大增幅2.44％。