Open FOAM Modelling of Particle Heating and Acceleration in Cold Spraying

Abstract

Abstract In cold spraying a powder material is accelerated and heated in the gas flow of a supersonic nozzle to velocities and temperatures that are sufficient to obtain cohesion of the particles to a substrate due to plastic deformation. The deposition efficiency of the powder particles is significantly determined by their velocity and temperature. The particle velocity correlates with the kinetic energy of the particles and thereby with the amount of energy that is converted to plastic deformation and thermal heating. The initial particle temperature significantly influences the mechanical properties of the particle. Velocity and temperature of the particles have nonlinear dependence on the pressure and temperature of the gas at the nozzle entrance. Whereas the particle velocity can easily be measured during the process, the particle temperature is not directly accessible by experimental techniques. Generally information about the particle temperature can be obtained based on theoretical models. In this contribution a simulation model based on the reactingParcelFoam solver of OpenFOAM is presented and applied for an analysis of the cold spray process. The model combines a compressible description of the gas flow in the nozzle with a Lagrangian particle tracking. The predictions of the simulation model are verified based on an analytical description of the gas flow, the particle acceleration and heating in the nozzle. Based on experimental data the drag model according to Plessis and Masliyah is identified to be best suited for OpenFOAM modelling particle heating and acceleration in cold spraying.