Optimum Fuel Gas Injections into Supersonic Hot Air Flows

本文研究了在马赫数为2的平行壁面气流中喷入燃气，以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入条件。氢气从与壁面齐平的圆孔中横向喷入，实验结果显示了强弓形激波的产生及其与激波边界层的相互作用，以及氢气与主流的湍流混合。当空气总温度升高到1000 ℃以上时，在试验段观察到自燃火焰。在单喷嘴的情况下，喷注器前的流动分离距离随喷注压力的增加而线性增加，氢射流内的桶形激波结构相应增大。氢气羽流在对流下游时保持相似的轮廓。另一方面，两个喷射器串联排列的情况下，揭示了两个喷射器之间的一个有趣的干扰区，该干扰区产生很小的静压变化和高的氢浓度。在试验段出口处测得的总压损失随两个喷射器之间的喷射压力比的变化而呈现最小值。这些结果表明，通过控制喷油器阵列模式可以优化燃油喷射。

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.