Experimental study on low-pressure ignition performance of a 3D rotating gliding arc plasma igniter

Achieving stable and reliable ignition of methane presents a critical challenge in space exploration activities. This paper proposed a 3D rotating gliding arc plasma igniter that is expected to enhance methane ignition in high-altitude or spatial environments. Discharge and low-pressure ignition experiments were carried out in a constant volume combustion chamber to check the ignition performance and the dominant parameters that matter the most. Results show that the discharge process firstly ionizes the working fluids and ignites the air/methane mixture via the plasma arc. The high-temperature products further ignite the surrounding unburned mixture, leading to secondary ignition, which can reflect the ignition speed. In the scale of this study, a high background pressure and slightly fuel rich environment helps to promote the ignition process and to increase the heat release rate. In a fixed environment, the excitation power dominates the heat release rate over frequency while the working gas equivalence ratio has limited influence in the scope of this study (<12.6% heat release rate variation). The findings provide insights into optimizing plasma igniters for practical aerospace propulsion systems operating in low-pressure environments.