Simulations And Measurements Of Alumina Particles In Plasma Spraying

A plasma spraying torch (Miller SG-100) has been studied by numerical modeling and Laser Doppler Velocimetry (LDV) techniques. Results are presented for axisymmetric turbulent argon plasma jets flowing into a cold air environment with the injection of alumina particles. The mathematical model involves the simultaneous solution of the continuity, momentum and energy equations for the plasma jet, and the dynamics and heat transfer of the particles in the plasma. Calculations are performed using the both parabolic and elliptic approaches. Turbulent effects are represented by the k-E model. The turbulent dispersion effect on the particles is also included. Coupling between the plasma jet and the particles is considered. -At a current of 900 A, plasma temperatures determined by modeling are compared with experimental results [l]. The difference is less than 4% at a distance less than 2 cm from the nozzle exit. At longer distance, plasma temperatures, obtained from modeling are about 3040% higher than those measured in [I] . At a current of 300 A, particle velocities obtained by the simulation are compared to LDV measurements with single and double injection. At a distance of 5.2 cm from the torch nozzle exit, particle velocities show a peak off-axis profile as measured by L,DV and as calculated by numerical modeling. Particle velocities determined from modeling are 20% higher than those measured by LDV at the axis. Differences between particle velocities determined from the parabolic and elliptic approaches are within 5%.