The effect of particle size and morphology on the in-flight behavior of particles during high-velocity oxyfuel thermal spraying

Abstract

A one-way coupled mathematical model is formulated to simulate the effects of particle size and morphology on the momentum and thermal energy transfer of particles during high-velocity oxyfuel (HVOF) thermal spraying. First, computational fluid dynamic techniques are implemented to solve the Favre-averaged mass, momentum, and energy conservation equations in the gas phase. The gas dynamic data are then used to model the behavior of particles in the gas field. The concept of sphericity is used to incorporate the effect of particle morphology into the model. The calculated results show that the particle velocity and temperature, before impinging onto the substrate, are strongly affected by particle size, morphology, and spray distance. Smaller particles are accelerated to a higher velocity but slowed down rapidly due to their smaller momentum inertia, while the larger particles are accelerated with some difficulty. The same tendency is observed regarding the effect of particle size on its thermal history.