Experimental study on energy characteristics and ignition performance of recessed multichannel plasma igniter*

Abstract

In the extreme conditions of high altitude, low temperature, low pressure, and high speed, the aircraft engine is prone to flameout and difficult to start secondary ignition, which makes reliable ignition of combustion chamber at high altitude become a worldwide problem. To solve this problem, a kind of multichannel plasma igniter with round cavity is proposed in this paper, the three-channel and five-channel igniters are compared with the traditional ones. The discharge energy of the three igniters was compared based on the electric energy test and the thermal energy test, and ignition experiments was conducted in the simulated high-altitude environment of the component combustion chamber. The results show that the recessed multichannel plasma igniter has higher discharge energy than the conventional spark igniter, which can increase the conversion efficiency of electric energy from 26% to 43%, and the conversion efficiency of thermal energy from 25% to 73%. The recessed multichannel plasma igniter can achieve greater spark penetration depth and excitation area, which both increase with the increase of height. At the same height, the inlet flow helps to increase the penetration depth of the spark. The recessed multichannel plasma igniter can widen the lean ignition boundary, and the maximum enrichment percentage of lean ignition boundary can reach 31%.

Fluid-chemical modeling of the near-cathode sheath formation process in a high current broken in DC air circuit breaker

“…[15,30] In particular, the high current arc has a high luminescence intensity, and hence the frequently-used plasma detection methods such as absorption spectrum and laser-induced fluorescence are no longer suitable for the detection of arc plasma. At present, the experiments on plasmas, including spectral diagnosis, [31,32] Langmuir probe [33] and high-speed imaging, [34,35] and so on are mostly focused on low density plasmas. The formation process of high current arc sheath lasts only tens of microseconds, and it is also difficult to observe the emission spectrum due to the limitation of the sampling rate of the spectrometer.…”