Scrutiny of spray jet and impact characteristics under dispersion effects of powder injection parameters in APS process

This study aims to analyse axisymmetric turbulent argon plasma jet charged with particle/droplet stream and its impact characteristics during atmospheric spraying process. The governing partial differential equations are solved using a double population lattice Boltzmann (LB) numerical model (D2Q9-D2Q4) coupled LES turbulence model. The powder dynamics and heating were modeled using a Lagrangian plasma-particles interaction model. A validation of the developed LB model on argon plasma jet was done, leading to credible results and the focus was thus mainly made on the plasma-particle exchanges during the powder journey in argon plasma. The effects of injection conditions on the spray stream of molten particles and the particles impacting conditions (velocity, temperature, melting rate, …) are carried out for four selected operating parameters, i.e. particle diameter, injection velocity, injection position (along injector section) and the injection angle at the injector exit. It has been observed that the LB method is a powerful tool for investigating plasma jet flows. It was concluded through the tracking model of the micro-sized particles that the present LB-based results agree well with the FD-based results and that the spray stream depends strongly on the studied injections conditions. Besides, the splashing phenomenon is found to be a rule governing particle/droplet impact behaviors.