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4712 |
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Influence of length of divergent and parallel section of the rectangular cross-section nozzle on behavior of particles of copper in high-pressure cold spray |
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Kazuhiko Sakaki* / SHINSHU University, Japan Shinji Arai/ Graduate School, Shinshu University, Japan Tatsuyuki Tagami/ Shinshu University, Japan Takashi Tschuida/ Shinshu University, Japan |
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In the cold spray process, cross-sectional shape of the nozzle has a significant effect on spray pattern of coatings. There is a rectangular and a circular cross-sectional shapes on the cold spray nozzle. It has been reported that 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. The most suitable expansion ratio was about around 12 without depending on a circular section and a rectangular section nozzle. In this study, CFD 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 behavior of the gas and copper particles in high-pressure cold spray. And we study about the influence of length of divergent section of the converging-diverging shaped rectangular cross-section (C-D-Re) nozzle. 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 and optimal divergent section length for C-D-Re nozzle. |