Simulation for the transition from non-thermal to thermal discharges

Abstract

A numerical algorithm is presented that characterizes the transition from non-thermal to thermal high-pressure gas discharges. To achieve this, the Poisson, charged particle continuity and Navier–Stokes equations are coupled together to analyse the interaction between the charged and neutral particles and the electric field. In this work, a new Navier–Stokes solver is developed based on the finite-element flux-corrected-transport method. This solver studies the movement of the neutral gas particles by solving the conservation of mass, momentum and energy for viscous fluids. The solver is thoroughly tested in both two-dimensional Cartesian and cylindrical axisymmetric coordinates. After validation, it is coupled to an existing Poisson and charged particle continuity solver through production and loss processes, momentum energy transfer and Joule heating effects. The avalanche and streamer discharges are analysed starting from a single electron and positive ion as initial conditions. Finally, the effect of including heating of the neutral gas on the electron density is discussed.