Influence of Rectangular Cross-Section Nozzle Shape on the Spray Pattern of Copper Coatings with HP Cold Spraying by CFD and experimental analysis

(Ratio of Length of Divergent and Parallel Section)

Abstract

In the cold spray process, cross-sectional shape of the nozzle has a significant effect on spray pattern of coatings. Spray pattern of the rectangular spray nozzle is wider than that of the circular spray nozzle. Accordingly, rectangular nozzle is better efficiency than circular nozzle at spray a constant width. The goal of this investigation is to establish a design for the cold spray gun nozzle in order to gain a flatter the spray pattern of coatings. We have investigated the effect of expansion ratio of rectangular nozzle on spray pattern of copper coatings in cold spraying by the computational fluid dynamics (CFD) and experiments. And the particle velocity and deposition efficiency of the copper coatings were dependent on the expansion ratio and geometry of the rectangular nozzle. In this study, CFD and experiments investigated the influence of length of divergent and parallel section of the converging-diverging parallel-shaped rectangular cross-section (C-D-Para-Re) nozzle on behaviours of the gas and copper particles (20μm) in high-pressure cold spray, and C-D-Re nozzle, too. As the results, it found that there is an optimal ratio of the length of the diverging section and the parallel section for C-D-Para-Re nozzle.