Nonequilibrium Thermal Plasma Jet Impinging on a Substrate

The interaction of a thermal plasma jet with a substrate is encountered in diverse technological applications, ranging from plasma spraying to toxic waste treatment and plasma gasification. The flow of a jet produced by a nontransferred arc plasma torch impinging on a flat substrate is simulated using a fully coupled thermodynamic nonequilibrium model. The modeling results indicate that the dynamics of the arc inside the torch cause the quasi-periodic movement of the jet, which leads to the formation of complex patterns in the heavy-species and electron temperature distributions, together with significant deviations from thermodynamic equilibrium, near the substrate. It is observed that the evolution of the degree of nonequilibrium near the substrate is strongly correlated with the direction of movement of the jet and, hence, with the arc dynamics inside the torch.