Ignition Energy Discharge of Oscillating Plasma Waveforms Under Atmospheric Conditions

Abstract

Oscillating plasma ignition is a promising technique to produce larger initial ignition volume. In this study, an energy waveform analysis of oscillating plasma discharge is investigated. To suffice the industrial applications, the challenges of plasma generation and control platforms are first discussed in this work. A flexible modulation for oscillating plasma generation is established, with the measurements of discharge voltage, secondary current, and discharge current. The phase difference between voltage and current is a critical effect on the energy waveform of oscillating plasma. In relevance to the command pulse train, the energy waveforms corresponding to various plasma discharging events are analyzed, which include normal, arc, and void cases. High-speed imaging, simultaneous with the electrical waveform measurements, is applied to record the plasma formation. Under elevated background pressures, the ignition volume of oscillating plasma is suppressed, and fewer plasma streamers can be observed. The prolonged duration and increased voltage consistently demonstrated positive impacts on flame propagation. This research added a foundation for the plasma diagnostics under engine-like conditions with variations of pressure, temperature, gas composition, and flow pattern.