Computational modeling of the HVOF process

Precise control of the high velocity oxygen-fuel spray (HVOF) process parameters is important to obtain high-performance coatings. The coating particle in-flight state is commonly monitored by measuring the in-flight temperature and velocity. To complement the available measurement techniques, a computational model for the gas flow and coating powder in flight, for propylene fueled HVOF process was built. The model is compared to measured nozzle exit pressure and position of the first shock diamond, together with measured particle velocities and surface temperatures. At first the gas flow is solved in absence of the coating powder, assuming a negligible powder mass flow, using the computational fluid dynamics (CFD) program “OpenFOAM”. Subsequently, the coating powder acceleration and heating is modeled in this gas flow.