Numerical Study of Suspension Plasma Spraying

TL;DR

This paper presents a detailed numerical model of suspension plasma spraying that considers droplet atomization, evaporation, and melting, analyzing how various parameters influence particle quality during flight and upon substrate impact.

Contribution

It introduces an advanced numerical model that incorporates high temperature gradients, non-continuum effects, and property changes due to evaporation in SPS processes.

Findings

Injection parameters significantly affect particle temperature and velocity.

Torch operating conditions influence particle melting and deposition quality.

Model predicts optimal parameters for improved coating quality.

Abstract

A numerical study of suspension plasma spraying (SPS) is presented in the current work. The liquid suspension jet is replaced with a train of droplets containing the suspension particles injected into the plasma flow. Atomization, evaporation, and melting of different components are considered for droplets and particles as they travel towards the substrate. Effect of different parameters on particle conditions during flight and upon impact on the substrate are investigated. Initially, influence of the torch operating conditions such as inlet flow rate and power are studied. Additionally, effect of injector parameters like injection location, flow rate, and angle are examined. The model used in current study takes high temperature gradients and non-continuum effects into account. Moreover, the important effect of change in physical properties of suspension droplets as a result of evaporation is included in the model. These mainly include variations in heat transfer properties and viscosity. Utilizing this improved model, several test cases have been considered to better evaluate the effect of different parameters on the quality of particles during flight and upon impact on the substrate.