Plasma spraying modeling: Particle injection in a time-fluctuating plasma jet

Due to the importance of the thermal and kinetic particle states at impact when generating a coating, numerical simulations of particle treatment in a plasma flow are continuously carried out in order to predict the particle behavior. The first goal is to correctly reproduce the plasma outflow in which the particles are introduced. This has been explored with a simplified model, the so-called heating volume model, to simulate industrial runs. Zirconia particles have been introduced in the simulated plasma flow and their melting state, velocity and trajectory have been compared with experimental measurements from specific in-flight-particle-capture and DPV 2000 devices. These comparisons highlight weak delays that depend on the particle size. This could be due, partially, to the particle heating assumptions (heat conduction within the particle) and to a poor knowledge of the thermal conductivity of liquid zirconia.