圆形出口内转式进气道流动特征

采用数值仿真的方法研究了内转式进气道的流动特征。研究表明:设计状态在近壁面唇罩激波诱发了二次流,进而发展形成流向涡,造成低能流堆积,隔离段出口流场分布不均,消弱了进气道的抗反压能力。有攻角条件下,口面激波偏离唇罩前缘,激波形态发生改变,激波波面中部展向具有准二维特性,压缩面两侧气流压缩变弱,激波层变薄,出现局部膨胀区;有攻角条件下的无黏流场,在进气道压缩段形成三维流向涡,该流向涡促进高能高速气流向壁面迁移,改善了黏性条件下隔离段出口流场的均匀度。

Flow characteristics of an inward turning inlet with circular outlet

The flow characteristics of an inward turning inlet are numerically studied. The results show that at design condition, the secondary flow near the wall is induced by the cowl shock and the streamwise vortex is generated in isolator, which will cause the flow with low velocity and low total pressure to accumulate. The distribution of the aerodynamic parameters at the isolator outlet is even, which will weaken the back-pressure capacity of inlet. With angle of attack, the compression shock departs the leading edge of cowl lip and the shock wave structure changes. The middle part of the shock wave presents quasi-two-dimensional feature in the span-wise. The shock wave is weak on the two sides of compression surface and the expansion waves occur in local zone. The streamwise vortex presents in the compression section without viscosity with angle of attack, and this streamwise vortex will enhance the transfer of the flow with high total pressure from the core flow region to the wall, so the evenness of flow at the outlet of isolator is improved under viscosity.