Abstract
In cold spray, optimum process conditions to accelerate particles vary with different densities and melting temperatures of the materials. Therefore, material-specific nozzle designs are required. In the present study, a nozzle geometry optimization concept based on 3D-CFD simulations was developed to provide a specific nozzle design for a given material. Al6061 and pure copper with mean particle diameters of 40 μm were taken as examples. Together with a design of experiments (DoE) approach, the model seeks for the optimal nozzle geometry. In order to reach the highest particle velocity prior to impact upon the substrate, different geometry parameters were varied, such as the nozzle throat cross section, the aspect ratio, and the nozzle divergent section length. The process gas was nitrogen with set stagnation pressure and temperature of 50 bars and 500 °C. For both materials, the simulation identified nozzle divergent section length as the most influential parameter, followed by the throat cross-section. The aspect ratio must be tuned to avoid over expansion of the gas in the nozzle.
