The role of particles flow characteristics in the performance of cold spray nozzles

Cold Spray(CS) is an emerging process, attracting much interest both as a coating and additive technique due to its solid-state nature and high deposition rates. The key element of any CS apparatus is the supersonic nozzle. The work presented here, for the first time, will explore in detail the relationship between particle flow, and its acceleration in the nozzle using Computational Fluid Dynamics and experimental measurements obtained with a Particle Tracking Velocimetry apparatus. We have developed modelling parameters capable to accurately predict the particle flow exit speed and space distribution, leading to considerably improved nozzle performances.