Effect of Ratio of Divergent to Parallel Length in Rectangular Cross Section Nozzle and Particle Size on Spray Pattern of Copper Coating by High Pressure Cold Spray

Abstract

In cold spray technology, the design of nozzle shape is important to generate the supersonic gas flow for sufficiently accelerates the particle and deposits as a coating. Among them, the spray pattern of coating was found to be affected by the design of nozzle shape especially length and ratio of divergent and parallel section, and copper coating was flattened by optimized rectangular cross section nozzle at previous study. However, in a recent study, thicker copper coating pattern with a view to molding in cold spray additive manufacturing was not flattened with the optimized nozzle, and it was necessary to review the nozzle dimensions for flatter copper coating and molding. In this study, in addition to review the nozzle ratio of length with particle size, CFD simulation conditions was improved due to mismatch of CFD and Experimental results. As a result, the spray pattern of copper coating is more flattened by the new optimized nozzle with a shorter divergent section, and moreover the pattern is possible to be estimated by the CFD.