Abstract A gliding arc discharge with an averaged power of 630 W at atmospheric pressure was used to ignite an ethylene-fueled scramjet combustor with an inflow speed of Mach number 2.92. The instantaneous power of the plasma and the high-speed CH* chemiluminescence imaging of the ignition process was simultaneously measured to show dynamic characteristics of the gliding arc plasma-assisted ignition. The results show that the power spikes of the spark-type discharges are the key factor to generate the flame kernel in the scramjet combustor and the instantaneous power can reach 3168 W during the power spikes. The flame kernel ignited by the gliding arc discharge can be developed to form an initial flame, which can become larger with increasing contained discharge energy of the gliding arc. Moreover, a comparison between the successful initial flame and the failed initial flame is performed to demonstrate that the larger area of the successful initial flame can propagate for achieving the mainstream flame, whereas the failed initial flame generated multiple times until the successful initial flame was observed. It is concluded that the successful initial flame contains more discharge energy during the initial flame formation, leading to form the resident flame in the recirculation zone.

中文翻译：

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腔式超燃冲压发动机滑弧等离子体辅助点火的动力学特性

摘要 采用大气压下平均功率为630 W的滑行电弧放电点燃流入速度为2.92马赫的乙烯燃料超燃冲压发动机燃烧室。同时测量等离子体的瞬时功率和点火过程的高速CH*化学发光成像，以显示滑弧等离子体辅助点火的动态特性。结果表明，火花式放电的功率尖峰是超燃冲压发动机燃烧室产生火焰核的关键因素，在功率尖峰期间瞬时功率可达3168 W。由滑动电弧放电点燃的火焰内核可以发展形成初始火焰，随着滑动电弧所含放电能量的增加，火焰内核会变得更大。而且，进行成功的初始火焰和失败的初始火焰之间的比较，以证明成功的初始火焰的更大面积可以传播以获得主流火焰，而失败的初始火焰产生多次直到观察到成功的初始火焰。得出的结论是，成功的初始火焰在初始火焰形成过程中包含更多的放电能量，导致在再循环区形成驻留火焰。