某典型二元高超声速进气道内二次流分析

Analysis of secondary vortex in a 2-D typical scramjet inlet

关键词:  超音速冲压喷气发动机  高超声速进气道  计算流体动力学  二次流

Key words:  Supersonic combustion ramjet engine  Hypersonic inlet  Computational fluid dynamics  Secondary flow

摘要:

对某典型二元高超声速进气道三维流场进行了数值分析, 将固壁面压力分布的计算结果与试验结果进行了比较, 二者吻合较好, 表明数值模拟方法正确, 结果可信。分析了高超声速进气道流场的波系结构以及进气道(含隔离段) 内二次流特征。给出了外压缩波系下的角涡的形成和发展规律, 在侧壁与压缩面相交角区形成为逆时针方向角涡, 角涡的形成、发展与近壁激波/侧壁附面层干扰以及压缩面有关。分析了隔离段中的激波的反射状况, 提出了隔离段二次流的形成和发展规律以及影响因素。在隔离段进口附近存在一分离区。隔离段内二次涡的形成、发展和消失由上下壁面的压差, 激波的移动方向(波后气流的横向流动) 等决定。研究还表明对于高超声速进气道即使是二元进气道, 也要关注二次涡的存在和发展。

Abstract:

The 3-D flow of a typical 2-D scramjet inlet was numerically simulated and the computational static pressure distribution on the wall were compared with the experimental data. The comparison showed that the numerical results agree quite well with the measurements. It implicated that the numerical simulation is corrective and creditable. The shock system and the characteristics of the secondary flow in the inlet (including isolator) were discussed. The formation and development of the corner vortex under external compression shock system were described. There is a counter-clock vortex at the corner between the sidewall and the compression surface. The formation and development of the vortex were affected by the shockwave / boundary layer on the side wall interaction and the location of compression surface. The shock reflection in the isolator was analyzed. The formation and development of the secondary vortex in the isolator and the influencing factors were presented. There was a separation region near the entrance of the isolator. The formation, development and vanish of the secondary vortex in the isolator were determined by the pressure difference between the upper and the lower walls and the moving direction of the shock waves (the cross flow post shock). It also showed that attention should be paid to the secondary vortex and its development for a hypersonic inlet and even for 2-D inlet.