Optimum Fuel Gas Injections into Supersonic Hot Air Flows

为了实现可靠的点火和燃烧、较短的燃烧长度和较小的总压损失，对平行壁面间2马赫气流中的燃油喷射进行了研究。氢气通过圆形孔横向注入，圆形孔安装在墙壁上，充当声波喷嘴。实验结果表明，强弓形激波的发生及其与激波边界层的相互作用，以及氢气进入主流的湍流混合。当空气总温度高于1000℃时，在试验区观察到自燃火焰。在单喷射器情况下，喷射器前方的流动分离距离随着喷射压力的增大而线性增大，氢气射流内的管状激波结构随之增大。氢羽流在向下游对流的过程中保持了类似的轮廓。另一方面，在两个喷嘴串联排列的情况下，两个喷嘴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。当两个喷油器之间的喷射压力比变化时，在测试段出口处测量的总压损失最小。这些结果表明，通过控制喷油器阵列模式可以实现燃油喷射的优化。

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.