Study of the arc root displacement and three-dimensional modelling of the thermal phenomena occurring in a hollow cathode submitted to an electric moving arc

Abstract

In order to have a better understanding of the thermal processes occurring in an electrode submitted to a moving arc root, we have studied the displacement mode of cathode and anode arc roots. We have also elaborated a three-dimensional model able to solve the diffusion problem of the heat brought by the arc root to a hollow cathode of a plasma torch. This model takes into account the temperature dependence of the material properties (specific heat and thermal conductivity), the various phase changes occurring during the arc and the arc root motion.