Numerical and experimental determination of plasma temperature during air plasma spraying with a multiple cathodes torch

A numerical model for the calculation of hydro and thermo dynamical gas flow in a three electric arc torch, considering electromagnetic influences on gas flow behaviour was described and developed. The modelling results were compared with experimentally determined temperatures, obtained by computer tomography. A characteristic threefold symmetrical distribution of temperature on the torch nozzle outlet was obtained numerically as well as experimentally. Calculated and tomographic temperature contours and their rotations were compared and showed good agreement. In the second step, a model for the free jet was used for the evolution of thermal conditions into plasma jet outside the torch. The comparison of the calculated temperature distributions and those determined by tomography exhibit good agreement.