喷口与凹面腔距离L对激波聚焦起爆爆震波的影响分析

The Investigation on the Influence of Distance between Jet Inlet and Concave Exit Plane on Detonation Initiation by Shock Wave Focusing

为研究两级脉冲爆震发动机环形喷口与凹面腔距离L对激波聚焦起爆爆震波的影响,文中以氢气和空气混合物为例,对不同L下激波聚焦起爆爆震波的过程进行了数值模拟。结果表明,L的存在会使激波入射方向与壁面法线方向夹角减小,在壁面反射聚焦的激波面积增大,腔内的反射聚焦效应增强;随着L的增大,起爆点与壁面间距离增加,起爆点压力下降;在L=1d附近,一个爆震循环作用于单位面积壁面的冲量最大。

In order to investigate the influence of the distance between jet inlet and concave exit plane on detonation initiation via shock wave focusing in a 2-stage PDE,detonation initiation with different L（the distance between jet inlet and concave exit plane） was simulated and hydrogen-air mixture was used in this paper.The results indicate that in the hemisphere concave cavity,the appropriate length of L can improve the incidence of leading shock at the concave wall to increase the reflected shock wave area and Aprrease the incidence angle and thus improve the reflecting effect.As L increases,the distance between the focus and concave wall is enlarged.Further more,when L=1d,the impulse on unit concave area is the largest during a detonation cycle.