Effects of Plasma–Suspension Interaction on Axial Injection DC Suspension Plasma Spray

Abstract

A rotationally axisymmetric 2-D numerical simulation of a dc suspension plasma spray (SPS) torch with an axial injection system is performed to discuss the interaction between the plasma fluid and suspensions. A two-way coupling model is used for modeling the behavior of plasma fluid and suspensions with mutual interaction effects through momentum and energy transfer. To deeply understand the mutual interaction effects, the numerical simulation using a one-way coupling model, in which the influence of suspensions on the characteristics of plasma fluid is not taken into account, is also performed for comparison. A suspension feed rate is parametrically varied to discuss its influence on the characteristics of plasma fluid and suspensions. Numerical results show that the two-way interaction substantially impacts the velocities and temperatures of plasma fluid and suspensions, and the trajectories of suspensions in the dc SPS torch with an axial injection system. It is also shown from the numerical results that the increase in suspension feed rate results in decreasing the electric current density around the central axis of the plasma torch and expanding the region with electric current in the radial direction.