In the extreme conditions of high altitude, low temperature, low pressure and high speed, the aircraft engine has a strong tendency to extinguish and it is then difficult to start secondary ignition, which means that re-ignition of the aircraft engine faces great challenges. Additionally, the ability of the single-channel gliding arc (1-GA) in assisting the ignition under extreme conditions is weak. In this paper, to solve this problem, a multichannel gliding arcs (MGA) system is proposed, using the principle of multichannel discharge. Experiments on the electrical characteristics and ignition performance of MGA were conducted under atmospheric pressure in a swirl model combustor. The electrical characteristics of MGA were investigated under different air velocities. The ignition process of MGA was recorded by using a high-speed camera with CH* filter. Results show that the three-channel gliding arcs (3-GA) and five-channel gliding arcs (5-GA) generated more averaged power than the 1-GA under a constant air velocity. For example, the 3-GA and 5-GA generated 112.8% and 187.3% more averaged power than that of the 1-GA at 74.6 m s−1, respectively. The arc shapes of gliding arcs with different channel numbers were different and the duration time of ‘breakdown-stretching-extinguishing’ of MGA shortened. Furthermore, compared with the 1-GA, the percentage of the lean ignition limit widening of the 3-GA and 5-GA can reach 13.5% and 20.9% respectively. The frequency of re-breakdown in the discharge process using different gliding arc channel numbers is different, which can continuously inject energy into the combustor and generate the ‘flame combination’ phenomenon producing a larger flame area. The ignition process of MGA can be divided into three stages: sliding stage, flame combination stage and flame stabilization stage.

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%.

A C-shape embedded multi-channel plasma igniter (CEMPI) is presented in this paper. Compared with traditional spark igniter (SI), it has a deeper penetration depth of fire kernel. The fuel supply pressure was kept at 0.2 MPa for the ignition tests. The ignition processes of two igniters at different air flow in a single-head swirl combustor were captured by using the technology of CH* chemiluminescence imaging. The influence of air flow on the ignition process and the ignition characteristics of two igniters were studied. The results show that the ignition dynamic process can be divided into four stages: fire kernel growth stage, flame stagnation stage, flame propagation stage and overall flame stage. To some extent, increasing air flow can shorten the ignition delay caused by flame stagnation, improve the flame propagation speed, and form overall flame earlier, which is conducive to fast ignition. Compared with SIs, CEMPIs can produce larger and more powerful fire kernel, which can penetrate deeper into the central recirculation zone and touch combustible mixture to generate initial flame. It also has a faster flame propagation speed to reduce the ignition time significantly. In addition, the CEMPI can widen the lean ignition boundary and has a more significant ignition advantage when the air flow is small.

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