NUMERICAL MODELING OF A DC NON-TRANSFERRED PLASMA TORCH: MOVEMENT OF THE ARC ANODE ATTACHMENT AND RESULTING ANODE EROSION

This paper describes a 3-D transient modeling of a DC plasma spray torch. The model of the arc column and its attachment on the anode wall is based on the simultaneous solutions of the conservation equations of mass, momentum, energy and the electromagnetism equations. It makes it possible to predict the motion of the anode attachment root on the anode surface as well as the heat load input to the anode surface at the spot location. The heat flux to anode is afterwards used as an input data for a 1-D enthalpy formulation model of anode heating that predicts the time-evolution of the thickness of the liquid layer on the surface at the anode spot and the quantity of vaporized material.