Gas dynamics and electromagnetic processes in high-current arc plasmas. Part I. Model formulation and steady-state solutions

A three-dimensional computational model has been developed to study the effects of self-induced and external magnetic fields, as well as gassing effects, on arcs involved in switching devices. A commercial computational fluid dynamics code has been adapted and modified to model the fully coupled plasma flow, heat transfer, and electromagnetic field. In this paper, a model is developed to analyze a steady-state, two-dimensional axisymmetric air arc column at low current levels under conditions in which the effects of the self-induced magnetic field are negligible. The model is then extended to analyze a three-dimensional arc column at high current levels with the inclusion of self-induced magnetic effects. The effects of cathode size, distance from the electrode, current level, self-induced magnetic field, and natural convection on the arc plasma are investigated. Predictions from these models compare favorably with published analytical and experimental results. The influence of external transverse magneti...