超燃燃烧室等离子体点火和火焰稳定性能

为了研究热等离子点火器在超燃冲压发动机中的应用,在来流马赫数2.0工况下,针对乙烯和氢气两种燃料,进行了超燃环境中等离子体点火的试验和仿真研究.在来流总温1 500~1 950 K,燃料当量比0.1~0.55范围内对等离子点火器的点火和改善燃烧性能的性质进行了详细分析.结果显示:对于氢气和乙烯燃料,等离子体点火器使两种燃料的点火性能均得到明显改善,点火延迟时间大大缩短,燃料着火范围扩大、贫燃极限当量比降低.但未观察到其在加速掺混以及改善燃烧性能方面的明显作用.进行了与乙烯燃烧试验对应的数值仿真工作,选用了两种乙烯化学反应模型进行对比研究.仿真结果显示:8步9组分反应模型与试验结果符合较好,而3步6组分反应模型过高的估计了反应剧烈程度,燃烧室压力值偏高,压力起始上升位置偏向上游.所用的8步模型比3步模型更适合于超燃燃烧室中乙烯反应的模拟.

Ignition and flame holding ability of plasma torch igniter in a supersonic flow

In order to study the application of plasma torch igniter in the scramjet engine, a numerical and experimental study was conducted in a Mach 2 supersonic flow with the ethylene and hydrogen. A detailed analysis of ignition and flame holding characteristics was done at the fuel equivalence ratio from 0.1 to 0.55, and the total temperature between 1 500 K and 1 950 K. The results show that the plasma torch has a positive effect on the ignition process, but the promotion on combustion efficiency is unapparent. An 8 step 9 species and a 3 step 6 species reaction model were used to simulate the ethylene supersonic combustion. The numerical results of 8 step reaction model agrees well with the experimental results.