Model and Powder Particle Heating, Melting, Resolidification, and Evaporation in Plasma Spraying Processes

Publisher Website
Google Scholar
Abstract
A comprehensive model is developed to study the heating, melting, evaporation, and resolidification of powder particles in plasma flames. The well-established LAVA code for plasma flame simulation is used to predict the plasma gas field under given power conditions, and provide inputs to the particle model. The particle is assumed to be a spherical and one-dimensional heat conduction equation with phase change within the particle is solved numerically using an appropriate coordinate transformation and finite difference method. Melting, vaporization, and resolidification interfaces are tracked and the particle vaporization is accounted for by the mass diffusion of vapor through the boundary layer around the particle. The effect of mass transfer on convective heat transfer is also included. Calculations have been carried out for a single particle injected into an Ar–H2 plasma jet. Zirconia and nickel are selected as solid particles because of their widespread industrial applications as well as significant differences in their thermal properties. Numerical results show strong nonisothermal effect of heating, especially for materials with low thermal conductivity, such as zirconia. The model also predicts strong evaporation of the material at high temperatures.

This publication has 27 references indexed in Scilit: