M. Boulos, Tekna Plasma Systems Inc., Sherbrooke, QC, Canada; D. V. Gravelle, Y. Lakaf, University of Sherbrooke, Sherbrooke, QC, Canada; S. Xue, Tekna Plasma Systems Inc, Sherbrokke, QC, Canada
A consistent thermal and chemical non-equilibrium model, developed recently, is applied to the modelling of pure argon supersonic plasma flow, which impinges on a substrate below the Mach 1 or mach 4 supersonic nozzle. Mach 1 nozzle consists of only a converged nozzle and so the maximum mach number at the nozzle exit is 1.0 at most but in the expansion region a few millimetres below the nozzle exit the mach number can reach above 5.0 depending on the total mass flow rate. The model considers the ionization of argon atom and recombination but the second order ionization is ignored and plasma charge neutrality is assumed. The collision cross-section data, published by Devoto and Murphy, are used to compute the plasma transport coefficients and mass diffusion coefficients. The model treats the subsonic discharge region above the supersonic nozzle and the supersonic region below the nozzle together. A few different numerical schemes and turbulent models are used for the modelling of the supersonic plasma flow. The radial and axial profiles of electron and heavy species temperatures and electron number densities near the substrate, obtained from the modelling are then compared with these measured by emission spectroscopy method and finally the best model is identified
Summary: A consistent thermal and chemical non-equilibrium model, developed recently, is applied to the modelling of pure argon supersonic plasma flow, which impinges on a substrate below the Mach 1 or mach 4 supersonic nozzle. Mach 1 nozzle consists of only a converged nozzle and so the maximum mach number at the nozzle exit is 1.0 at most but in the expansion region a few millimetres below the nozzle exit the mach number can reach above 5.0 depending on the total mass flow rate. The model considers the ionization of argon atom and recombination but the second order ionization is ignored and plasma charge neutrality is assumed. The collision cross-section data, published by Devoto and Murphy, are used to compute the plasma transport coefficients and mass diffusion coefficients. The model treats the subsonic discharge region above the supersonic nozzle and the supersonic region below the nozzle together. A few different numerical schemes and turbulent models are used for the modelling of the supersonic plasma flow. The radial and axial profiles of electron and heavy species temperatures and electron number densities near the substrate, obtained from the modelling are then compared with these measured by emission spectroscopy method and finally the best model is identified
