CFD Optimised Nozzles for Increased Particle Velocities and Lowered Gas Consumption in the HVOF Spraying Process

Well-adjusted processing conditions are the basics for a high quality of thermal sprayed coatings. For HVOF spraying that means super sonic particle velocities and moderate particle temperatures. To fulfil these requirements, a certain speed of the gas jet is necessary. If low fuel and gas consumption is aspired, this can only be realised with adapted nozzle designs. Some efficient ways of nozzle design optimisation are shown in this paper. Novel methods and strategies in computed fluid dynamics are explained and correlated to experimental results. For this purpose, gas jet and particle velocities are investigated by means of laser optical measurements.