NUMERICAL MODELING OF ARC BEHAVIOR IN A DC PLASMA TORCH

Abstract

This paper describes a three-dimensional time-dependent model of a direct current plasma torch when the arc operates in the restrike mode. The model is based on the simultaneous solution of the conservation equations of mass, momentum, energy, electric current and electromagnetic equations. It makes it possible to predict the effect of the operating parameters of the plasma torch on the motion of the attachment root on the anode surface and the time-evolution of the gas flow fields inside the nozzle. The simulations, carried out for a conventional plasma spray torch, show that the model gives the good tendencies when a torch parameter is varied, and that the predicted values of gas temperature and velocity at the nozzle exit agree with the experimental values.