一种改善高超声速进气道自起动能力的流场控制研究

为了改善高超声速进气道在低马赫数下的自起动能力,提出了一种在进气道内利用不起动时诱导激波前后静压差开设回流通道的流场控制概念,对其改善流场特性的机理及回流通道典型几何参数对进气道流场特性和气动性能的影响进行了分析,获得了回流通道典型几何参数对进气道自起动性能的影响规律,并与原型面进气道性能进行对比分析。结果表明:回流通道使进气道自起动马赫数由Ma=4.7降低至Ma=3.6,进气道工作马赫数范围得到显著拓宽;回流通道进口位置对进气道自起动马赫数存在较大影响,但自起动马赫数几乎不随回流通道出口位置、回流通道宽度(b≥8mm)而改变;在低马赫数时,回流通道对进气道不起动流场有明显改善。而高马赫数下回流通道对进气道性能几乎不产生影响,保证了高马赫数下进气道的性能。

A flow-control conception of improving self-start performance of hypersonic inlet

To improve the self-start performance of hypersonic inlet at low Mach number, a flow-control conception of backflow duct is put forward, which is driven by the pressure difference generated by the separation induced shock under unstart conditions. The influencing principles are analyzed, and the characteristics of inlet''s flow field and the inlet''s aerodynamic performances affected by variable geometry parameters of the backflow duct are investigated. Finally, compared with the primary inlet''s performances, the results indicate that due to the backflow duct, the self-start Mach number is ascended from Ma=4.7 to Ma=3.6, expending the operating Mach range remarkably. The location of the backflow duct''s entrance influences the self-start performance significantly, while the location of backflow duct''s exit and the width of backflow duct''s section (b≥8 mm)scarcely affectes the self-start ability. At low Mach number, the unstarted flow field of inlet is improved by the backflow duct considerably.But at high Mach number, the influence of backflow duct would be slight, satisfying the design performance requirements.