Effects of gliding arc plasma on ignition and extinction flame evolution in combustors under low pressure conditions

To address the issues of ignition and flame extinction in the combustion chamber of a small turbine engine under high-altitude and low-pressure conditions, a gliding arc plasma-assisted ignition and combustion dome was integrated into the combustor. Based on a low-pressure combustion test platform, experiments were conducted to characterize low-pressure discharge dynamics, ignition performance, and flame extinction performance. Systematic comparisons were performed on discharge characteristics, flame evolution processes, and lean-blowout boundaries across varying pressures. Results show that at 80 kPa and 300 L/min, the plasma-assisted ignition and combustion dome exhibited reduced electrical parameters: peak-to-peak voltage decreased to 2 kV, maximum peak voltage to 5 kV, and discharge cycle to 2.2 ms, average discharge power increases to 137 W (90 kPa) and then decreases to 111.6 W(75 kPa) comparing with that via atmospheric operation. Gliding arc plasma significantly broadened the ignition and flameout limits, achieving a 13.5% expansion in ignition limits and a 40.4% reduction in ignition delay time relative to conventional spark ignition. Furthermore, at 90 kPa, the flameout limit was extended by 16.4%. The present study provides the critical insights into plasma-assisted ignition and combustion mechanisms under low-pressure conditions, advancing the design of reliable combustion systems for high-altitude aerospace applications.