一种平面埋入式进气道的地面工作特性及流态特征

对一种平面埋入式进气道的地面工作特性进行了实验研究,结合数值仿真技术,分析了地面工作状态下该类进气道的流态特征,并探讨了其出口总压图谱的形成成因.结果表明:(1) 虽然进气道出口截面的二次流较弱,但通道内却存在强的以对涡为特征的旋流,该对涡因埋入式进气道进口侧棱的存在而产生,与后唇口前缘的气流分离共同导致了进气道出口截面的大面积低总压区;(2) 地面工作状态下,埋入式进气道的总压恢复系数随出口马赫数的上升而下降,周向畸变指数、紊流度和综合畸变指数则随着出口马赫数的增加而增加.在相同的出口马赫数下,地面工作状态的总压恢复系数高于飞行状态,各种畸变指数也明显偏高.但当发动机的进口工作马赫数为0.35左右时,进气道出口截面的综合畸变指数W小于10.0%,满足常规发动机的稳定工作要求;(3) 计算和实验结果对比表明,所得到的进气道出口总压恢复系数相对误差在1.2%以内,但畸变指数整体偏大.

Experimental and computational study of a submermerged inlet on the plane surface under ground running

Utilizing the combined experimental and computational method,the aerodynamic performance and internal flow pattern of a submerged inlet on the plane surface under ground running are obtained in this paper.Results indicate that:(1) The secondary flow at the cross sections behaves as two counter-rotating vortices which are originated by the side edge of the entrance.The ongoing vortex pair interacts with the separated flow near the aft lip of the inlet and results in the low total pressure region at the bottom surface of the exit.(2)With the ascent of Mach number at the exit,both the total pressure loss and distortion index increases.In spite of a remarkable shift of the distortion index under ground running,compared with high speed wind tunnel tests,the synthesis distortion index is kept below 10.0% at the maximum RPM which does not threaten the stable operation of the engine.(3) The CFD results agree well with the experiment and the relative errors of the total pressure coefficient is less than 1.2% though the distortion index by CFD is a bit higher.