Numerical model of a transferred plasma arc

This article presents results of two-dimensional simulations for a transferred plasma arc. Calculations are performed for the internal plasma flow within the torch body, as well as the external plasma jet impinging on a surface. The governing equations describing the plasma flow are self-consistently coupled. These equations are the compressible Navier-Stokes equations for conservation of mass and momentum (in the radial and streamwise directions), conservation of energy, species continuity with finite-rate ionization and recombination kinetics, and the magnetic diffusion equation for the electromagnetics. The unsteady forms of these equations are time marched to steady state using the linearized block implicit method. This model does not employ any adjustable parameters, and therefore enables direct comparison with experiments. Model predictions are compared with experimental measurements of stagnation pressure distributions recorded on a water-cooled copper plate (workpiece), and indicate good agreement, given the lack of adjustable parameters. (C) 1998 American Institute of Physics. [S0021-8979(98)07419-2].