Particle Acceleration Through Coaxial Co-Flow Nozzles for Cold Spray Applications

The present study numerically investigates the effectiveness of co-flowing nozzles for cold spray applications. A convergent-divergent axi-symmetric nozzle system was simulated with high-pressure nitrogen flow. The particle acceleration is modelled by a two-way Lagrangian approach and validated with reference to experimental values reported in the literature. An annular co-flowing nozzle with circular central nozzle was simulated for nitrogen gas flow. The momentum preservation for central nozzle flow was observed, which results in higher particle speed for longer axial distance after nozzle exit. It is envisioned from the outcome that utilization of co-flow can lead to reduction in the divergent section length of cold spray central nozzles, which may ultimately help to address clogging issues for continuous operation. Co-flow operating at 3 MPa, same as with a central nozzle, can increase supersonic core length up to 23.8%.