Experimental investigation of a gliding discharge plasma jet igniter

Relight of jet engines at high altitude is difficult due to the relatively low pressure and temperature of inlet air. The penetration of initial flame kernel affects the ignition probability in the turbine engine combustor greatly. In order to achieve successful ignition at high altitude, a deeper penetration of initial flame kernel should be generated. In this study, a Gliding Arc Plasma Jet Igniter (GAPJI) is designed to induce initial flame kernel with deeper penetration to achieve successful ignition at high altitude. The ignition performance of the GAPJI was demonstrated in a model combustor. It was found that GAPJI can generate plasma with deeper penetration up to 30.5 mm than spark igniter with 22.1 mm. The discharge power of GAPJI was positively correlated with flow rate of the carrier gas, approaching 200 W in average. Ignition experiments show that GAPJI has the advantage of extending the lean ignition limit. With GAPJI, the lean ignition limit of the combustor is 0.02 at 0 km, which is 55.6% less than that with spark igniter (0.045). The evolution of flame morphology was observed to explore the development of the flame kernel. It is shown that the advantage of a high penetration and continuous releasing energy can accelerate the ignition process and enhance combustion.