基于支板凹腔结构的超燃燃烧室数值研究

Numerical Study on Strut/Cavity-Based Scramjet Combustor

为探究基于支板凹腔结构的超燃燃烧室性能,在超声速来流条件下,采用带中心支板且凹腔长高比为7.5的三维超燃燃烧室模型,针对支板阻塞比、扩张段扩张角、不同燃料喷射方式以及不同燃料当量比对燃烧室相关性能的影响进行了数值研究。研究发现:支板阻塞比会对隔离段内的激波分布以及支板后缘速度分布产生明显影响,而扩张段扩张角会影响超声气流在燃烧室出口的膨胀状态;采用壁面以及中心喷注支板同时喷油方式在保持高燃烧效率的同时会扩大整个燃烧室的燃烧区域;当采用单独壁面喷油方式时,凹腔内静温分布会随着当量比的变化发生相应的改变,同时会在当量比为0.51~0.74时达到相对较高的燃烧效率。

In order to investigate the performance of a scramjet combustor with strut/cavity integrated con- figurations, numerical simulation on a three dimensional scramjet combustor model with a center injection strut and a cavity （L/D=7.5） was performed under supersonic flows. The effects of strut choke ratio, expansion angle of divergent section, various injection modes and equivalence ratio on performances of scramjet combustor were analyzed and compared. The results showed that strut choke ratio had great effect on the distribution of shock wave in the isolator and the velocity distribution on the strut trailing edge. And the expansion angle of divergent section may influence flow＇ s expansion state at the combustor exit. Injection from both the combustor wall and the strut may serve as an effective tool in expanding the combustion region while keeping high combustion efficiency. When injection just from the combustor wall, the static temperature in cavity changed with the change of the equivalence ratio and the combustion efficiency will reach a relatively high point when the equivalence ratio between 0.51 and 0.74.