Effect of voltage polarity on reaction mechanism of air atmospheric surface dielectric barrier discharge: A numerical study

Abstract

This study establishes a two-dimensional fluid model of nanosecond surface dielectric barrier discharge (nSDBD) at atmospheric air to investigate the effects of positive and negative sinusoidal nanosecond pulsed voltages on the discharge characteristics. Key discharge parameters are studied, including discharge current, distribution of major active particles, surface charge distribution on the dielectric, energy deposition density distribution, and gas temperature. The numerical simulation results indicate that the plasma streamers excited by positive and negative bipolar pulses exhibit markedly different discharge characteristics, with the discharge characteristics in the first half-cycle largely determining those of the entire cycle. Positive bipolar pulsed streamer discharges exhibit greater discharge currents and stronger local electric fields, with faster propagation speeds but also more pronounced declines. The energy deposition of positive bipolar pulse is higher than that of negative bipolar pulse. The discharges driven by negative bipolar pulses exhibit a more pronounced temperature rise effect, primarily due to their higher efficiency in converting electrical energy into thermal energy, leading to stronger localized thermal release. Consequently, the pressure waves generated by negative bipolar pulsed discharges are more intense. These numerical simulation data provide theoretical explanations and references for understanding and optimizing the physical mechanisms of nSDBD.