扩压式双S隐身进气道设计和流场分析

采用扩压式双S隐身进气道能够提高飞行器的隐身特性和综合性能。针对保形短程、高隐身、大偏距的亚音速隐身无人机进气道,以保形入口、中间控制面和出口截面为约束并结合多项式对中心线和面积、截面形状进行控制,实现对保形进口截面形状和弯曲形式复杂的双S隐身进气道的快速设计;在此基础上,研究中心线曲率、面积分布和中间截面形状等参数对进气道性能的影响。结果表明:双S进气道流场特性复杂,第二S弯处顶部的分离和空间二次涡引发的流场畸变的综合控制是设计的重点,通过截面参数约束并结合多项式能够对双S进气道内的流场品质进行控制;在中心线曲率、扩张角和多项式参数等配制上应该朝利于第二S弯流场稳定的方向靠近。

Investigation on the design and flow characteristics of diffusing serpentine Inlets

A cross-sectional shape generating method for the compact and offset bend double-S-inlet design of subsonic stealthy UAV is proposed according to curvature regulation. The inlet design procedure can quickly accomplish the surface composition of Double-S-inlet with complex conformal intake shape and complex bending style. Utilizing that method, six ducts are created and multi-parameters which include centerline curvature, area ratio and middle-cross-sectional shape are analyzed to studied the effects on duct perforce. Results indicate that the reverses at the top region of the second S part and the total pressure distortion arose by secondary flow should be considered carefully in the Serpentine inlet design procedure. Results also indicate that there are more complex flow structure in the Serpentine inlet compared to that in the S-duct inlet, and that the conventional design approach used in the S-duct inlet is still effective in the double-S-inlet design procedure.