Optimal Design of Nozzle for Supersonic Atmosphere Plasma Spraying

摘要

Through numerical simulation, key issues concerning the plasma jet features as well as the sizes of nozzle for supersonic atmosphere plasma spraying (SAPS) were analyzed in this paper. Numerical results were compared with the experimental measurements and a good agreement has been achieved. Due to the effect of mechanical compression, the increasing sizes of r_1, r_2, r_3 and r_4 (r_1, r_2, r_3 and r_4 are the sizes of nozzle) lead to a decrease in temperature and velocity of plasma jet. But large size of r_5 can increase the external temperature and velocity of plasma jet, which benefit particles accelerating at the far downstream region. A new nozzle was designed based on the simulation results. Compared to the temperature and velocity of plasma jet in the original nozzle, the maximum temperature and velocity of plasma jet in new structure are increased by about 9.8% and 44.5%, which is a benefit to the particles to reach a higher speed and surface temperature.