Numerical and Experimental Investigation to the Melting Mechanism of Granular Powders for Vitrification by Induction Thermal Plasmas

摘要

In this contribution the melting mechanism of granular raw powders in an induction thermal plasma reactor for glass production has been described from both numerical and experimental point of views. Simulation has been performed to predict the flow and temperature fields within the plasma torch for various flow conditions of carrier gas using a 2-dimensional LTE (local thermodynamic equilibrium) model including a metal tube inserted into the torch for powder and carrier gas injection. Simulated results revealed that the higher the flow-rate of carrier gas, the lower the temperature profiles around the centerline of the torch, and the higher the axial plasma velocity. The average particle size of quenched powders became smaller and the softening temperature decreased with higher flow-rate of carrier gas, because of shorter relaxation time and lower temperature respectively. The numerical results well explained the experimental findings and provided a roadmap for the parameter optimization in the melting process.