NUMERICAL-MODEL OF A TRANSFERRED PLASMA-ARC

This article presents results of two-dimensional simulations for a tra nsferred plasma arc. Calculations are performed for the internal plasm a flow within the torch body, as well as the external plasma jet impin ging on a surface. The governing equations describing the plasma flow are self-consistently coupled. These equations are the compressible Na vier-Stokes equations for conservation of mass and momentum (in the ra dial and streamwise directions), conservation of energy, species conti nuity with finite-rate ionization and recombination kinetics, and the magnetic diffusion equation for the electromagnetics. The unsteady for ms of these equations are time marched to steady state using the linea rized 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 stag nation 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)07 419-2].