Thermal Treatment of Al_2O_3, MgO, and CeO_2 Granulated Powders by Induction Thermal Plasma: A Numerical Approach

摘要

A plasma-particle interactive flow model has been developed for the investigation of plasma temperature, velocity, particle temperature, diameter, and flight path during in-fight thermal treatment of granulated powders-Al_2O_3, MgO, and CeO2 in induction thermal plasma, taking into account of plasma particle interaction and particle loading effects. In this model, the conservative equations are solved to investigate the influence of feed-rate and particle diameter on the melting behavior of granulated powders and to predict particle trajectories, temperature histories etc. In this paper attention is given to the effects of carrier gas flow-rate, powder feed-rate and secondary gas (oxygen) flow-rate on the particles' final diameter and trajectory for Al_2O_3, MgO, and CeO_2 powders. Results show that the particles diameter after thermal treatment is strongly dependent on the powder feed-rate, oxygen gas flow-rate and carrier gas flow-rate. Among the three types of powders, particle diameter decrement is significant in case of MgO and less significant in case of Al_2O_3; and the effect of oxygen flow-rate on the particle diameter decrement is significant in case of MgO. Particles trajectories are wider for smaller particles than that of larger particles. Particle temperature is lowest for MgO and highest for Al_2O_3 particles.