Influence of shape edge of the rectangular cross-section nozzle on the velocity and temperature of gas and particles in high-pressure cold spraying by the computational fluid dynamics (CFD)

In the cold spray process, cross-sectional shape of the nozzle has a significant effect on spray pattern of coatings. It has been reported that the rectangular nozzle provide a more uniform particle velocity across the exit of the nozzle. The circular exit nozzle is parabolic in shape. So spray pattern with the rectangular nozzle is wider than that with the circular spray nozzle. We have investigated the influence of expansion ratio, nozzle total length and the ratio of nozzle length of divergent section and parallel section of rectangular nozzle on behaviors of gas and particle by the computational fluid dynamics (CFD) in high pressure cold spraying.

In this study, influence of shape edge of the rectangular cross-section nozzle on the velocity and temperature of gas and particles in high-pressure cold spraying using CFD code such as ANSYS Fluent are reported.　The nozzle shape was convergent-divergent type. The shape edge of the rectangular cross-section of nozzle divergent section was two types, corner radius and square shape. The impact velocity of copper particle on the central axis of the nozzle with the circular corner nozzle was higher by 10 m / s than that with the square shape corner nozzle.