飞翼无人机3种保形进气口进气道气动与隐身综合特性对比

基于飞翼布局无人机隐身与结构装载布置要求,保形设计了3种进气口形状的背负式S弯进气道,按照进口投影截面形状上、下底之比顺序排列,分别为三角形、梯形和矩形.利用数值模拟方法对无人机内外流场耦合流动进行计算分析,且基于射线弹跳(SBR)法对进气道电磁散射特性进行仿真研究,获得了飞翼无人机3种进气道的气动与隐身综合特性.研究结果表明:1矩形进气道模型升阻和纵向力矩特性表现均最好;23种进气道模型按顺序排列总压恢复系数逐渐增大,畸变指数逐渐减小,进气道沿程气流也逐渐顺畅,矩形进气道模型进气道内流特性最优;30°迎角下3种进气道模型雷达散射截面(RCS)均值基本呈现先增大后减小的特征,进气道终端开放时矩形进气道模型隐身性能最好,而终端短路时三角形进气道模型隐身效果更优异.

Comparison on aerodynamic and stealthy performanceof flying wing unmanned aerial vehicle withthree conformal intake inlets

Based on stealth and structural loading requirements of flying wing unmanned aerial vehicle (UVA), three dorsal S-shaped inlets with three conformal intakes were designed. According to the ratio of the upper and bottom of the sectional projection shape of the intake, three inlets, i.e.: triangular, trapezoidal and rectangular inlets, were named. The coupled numerical simulation was carried out on the inflow/outflow integrated for flying wing UAV, and the simulation method based on shooting and bouncing ray (SBR) was also performed to study the electromagnetic scattering of inlet. Then the aerodynamic and stealthy performance of flying wing UAV with three conformal inlets was obtained. Results indicate: (1) The lift/drag and the longitudinal moment characteristic of the model with rectangular inlet are the best.(2) As the three inlet models are arranged in previous order, the total pressure recovery coefficient increases gradually, and the distortion coefficient decreases; moreover, the airflow along the inlet becomes smooth gradually, and then, of course, the internal flow characteristic of the model with rectangular inlet shows the best.(3) At the attack angle 0° the mean value of the three inlet models radar cross-section (RCS) increases first and then decreases basically.The stealthy performance of the model with rectangular inlet is the best with the terminator open, but the model with triangular inlet shows better when the terminator is short-circuited.