内压缩波系对高超声速进气道自起动性能影响研究

Effect of the inlet internal compression shock waves on restart characteristics of the hypersonic inlets

为了探究进气道肩部膨胀扇以及不同压缩方式对进气道自起动性能的影响,结合具体的进气道构型,针对不同的压缩角、边界层厚度开展了马赫数4.0级的风洞试验研究。结果表明:在不起动分离区同侧的膨胀扇会对当地气流加速,降低局部压强,进而对压缩激波较强时的进气道自起动过程有明显改善。而唇罩分级压缩对二元进气道的自起动能力也有提高效果。此外,对比侧压模型与顶压模型的试验结果发现,边界层厚度对侧压模型自起动性能的影响趋势与顶压式存在明显的差异。与此同时,当自起动受限于几何喉道的进气道构型,压缩方式对进气道自起动性能的影响不明显,但是对于由压缩激波-边界层干扰诱导分离区形成的气动喉道决定能否起动的进气道,侧压方式有利于提高进气道的自起动性能。

The specific hypersonic inlet models have been tested at Ma =4.0 wind tunnel to enrich the understanding of the effect of expansion waves on the inlet shoulder and the different compression ways on the inlet restart characteristics. The cowl angle and the thickness of the boundary layer have been regarded as the key influence factors. Results show that the expansion waves originated from the shoulder accelerate the local flow velocity and decrease the static pressure, which promotes the separation to move downstream. Thus, the inlet restart capability can be enhanced. And the multiple noncoalesced cowl shock waves can also improve the two-dimensional inlet restart capability. Due to the obvious three-dimensional structure of the separation induced by the swept shock, the inlet restart performance of sidewall-compression inlet differs from that of the cowl compression inlet. For the un-restart inlet caused by aerodynamic throat choke, the sidewall-compression can enhance the inlet restart capability effectively compared to the cowl-compression.