Published 4 issues per year
ISSN Print: 1093-3611
ISSN Online: 1940-4360
Indexed in
MATHEMATICAL MODELING OF THE SUPERSONIC D.C. PLASMA SPRAY TORCH: INFLUENCE OF HYDROGEN AND CURRENT INTENSITY
ABSTRACT
The effects of current intensity and hydrogen on argon supersonic plasma flow inside a d.c. torch are investigated in order to gain insight of the flow structure and transfer mechanisms inside the torch. A two-dimensional axisymmetric model and a non-equilibrium cathode sheath model are used for this purpose. The model is validated by comparison with published experiments and good agreement is found between the model and the measurements. The study describes the aerodynamic, thermal and electrical fields inside the nozzle. It reveals that the presence of hydrogen changes considerably the plasma features. The study of the current intensity influence gives the trend and values of the operating conditions for the optimal use of the system for spraying applications. This study shows that the effect of the current intensity on the flow is different from the subsonic cases. It also indicates that a maximum current exists, beyond which the flow at the exit is not completely supersonic.