Numerical Investigation on the Flame Characteristics and Particle Behaviors in a HVOF Spray Process Using Kerosene as Fuel

HVOF coatings generally have a high bonding strength and good compactness, which improve the wear, corrosion, high-temperature oxidation, and fatigue properties of the substrate. They are widely used in automobile, home appliance, petrochemical, aerospace, and other fields. The flame flow characteristics and particle in-flight behaviors during the spray process have an essential influence on the coating microstructure and, thus, properties. This paper deals with a flow field model of a HVOF process that uses kerosene as fuel. A one-step chemical reaction model and the eddy dissipation model were used to numerically calculate the flame dynamics. The numerical simulations predicted the variation laws of flame pressure, temperature, velocity, Mach number, and combustion components. On this basis, the temperature, velocity, and trajectory of WC-12Co particles were calculated using a Lagrangian approach. The effect of the oxygen/fuel ratio on the flame flow and particles characteristics was analyzed, as well as the effect of particle diameter, shape, injection angle, and nitrogen flow rate on particle in-flight processing.