Optimum Fuel Gas Injections into Supersonic Hot Air Flows

为了获得满足可靠点火和燃烧、较短燃烧长度和较小总压损失的最佳喷油条件，对马赫数为2的平行壁间气流喷气进行了研究。氢气通过安装在壁面上的圆孔作为音速喷嘴进行横向喷射，实验结果表明，发生了强烈的弓形激波和与之相关的激波边界层相互作用，以及氢气在主流中的湍流混合。当空气总温度升高到1000ﾟC以上时，在试验段观察到自燃火焰。在单喷嘴的情况下，喷嘴前方的流动分离距离随着喷射压力的增大而线性增大，氢气射流内的筒状激波结构相应增大。氢羽流保持了与下游对流相似的轮廓。另一方面，在两个喷射器串联的情况下，两个喷射器之间有一个有趣的干扰区，产生的静压变化很小，氢气浓度很高。在试验段出口处测得的总压损失随两个喷油器之间的喷油压力比的变化而最小。这些结果表明，可以通过控制喷油器阵列图案来优化燃油喷射。

Fuel gas injection into Mach 2 air flows between parallel walls has been investigated in order to achieve optimum fuel injection conditions that satisfy reliable ignition and flaming, shorter combustion length and less totalpressure loss. Hydrogen gas has been transversely injected through circular holes which are mounted flush to the walls and act as sonic nozzles.Experimental results show the occurrence of strong bow shock wave and the associated shock wave boundary layer interaction as well as the turbulent mixing of the hydrogen into the main flow. When the total temperature of air was raised above 1000ﾟC, the self-ignition flame was observed at the test section. In case of a single, injector the flow separation distance ahead of the injector increased linearly with the injection pressure and the barrel shock wave structure within the hydrogen jet was enlarged accordingly. The hydrogen plume kept similar profile as it was convected downstream. The case of two injectors arrayed in tandem, on the other hand, revealed an interesting interference zone between the two injectors that yielded little static pressure variation and high hydrogen concentration. The total pressure loss measured at the test section exit showed a minimum as the injection pressure ratio between the two injectors was varied. Those results indicated the possible optimization of the fuel injection by the control of the injector array patterns.