Simulation of Positive DC Corona Streamer Pulse Characteristics at Various Air Pressures and Humidities

The simulation of positive dc corona streamer pulse characteristics at various air pressures and humidities for a rod-plane electrode system has been investigated. A flux-corrected transport (FCT) algorithm, based on a non-uniform mesh, and a successive over-relaxation (SOR) algorithm were applied to solve the continuity equations and Poisson equation in a fluid model to produce positive streamer pulse waveforms. The values of the various coefficients for humid air, considered as a gas mixture of air and water vapor and necessary for the calculations, were estimated by linear interpolation from the values for the separate 'gases'. The simulation results were in general agreement with the experimental ones of our previous study. The positive streamer average amplitude decreased as the pressure was reduced or the humidity was raised. The phenomenon was explained by the decreasing of the average electric field and the conductivity in the discharge channel.