Effect Of Substrate Curvature On In-flight Particle Characteristics In Suspension Plasma Spraying

Obtaining a uniform coating on mechanical parts with curved surfaces such as gas turbine blades is one of the challenges in suspension plasma spraying. Through a three dimensional numerical analysis, this study is aimed to provide a better understanding of the effect of substrate curvature on in-flight particle temperature, velocity and trajectory. The plasma flow is simulated inside the plasma torch nozzle by means of using a constant volumetric heat source added in the energy equation while suspension is molded as a multicomponent droplet. Particle size distribution in the vicinity of the substrate at different stand-off distances has been investigated. The results show that sub-micron particles may obtain higher velocity and temperature compared to the larger particles. However, due to the small Stokes number associated with sub-micron particles, they are more sensitive to the change of the gas flow streamlines in the vicinity of a curved substrate.