Modeling influence of basic operation parameters on plasma jet

In plasma spray, operation parameters, including current, flow rate of primary gas, and flow rate of secondary gas, would influence the heat and acceleration status of particles greatly, thus influencing the coating's final quality. As the first stage to optimize the spraying technology, this paper investigates the typical Ar-He plasma spray process, analyzing the influence mechanism of current, flow rate of Ar, as well as flow rate of He on the temperature field and velocity field. The chemical reactions and turbulence are fully taken into account. It is found that the electrical current is apparently influential to both the jet temperature and velocity, and further the ionization of Ar atoms. With increasing Ar or He flow rates independently, the temperature of theplasma jet will be decreased, and the velocity of the plasma jet will be increased. Related inner mechanisms are revealed in detail. The results presented in this paper would be theoretically helpful for further study of the interaction between the plasma jet and the particles, and the optimization of the plasma-spraying technology. @ 2007 Elsevier B.V. All rights reserved.