Abstract No.:
3654

 Scheduled at:
Friday, May 23, 2014, Hall A 11:00 AM
Process Diagnostics, Sensors & Controls


 Title:
Modeling the gas flow and coating particle dynamics in hydrogen and propylene fueled HVOF processes

 Authors:
Tatu Pinomaa* / VTT Technical Research Centre of Finland, Finland
Tomi Suhonen / VTT Technical Research Centre of Finland, Finland
Tommi Varis/ VTT Technical Research Centre of Finland, Finland

 Abstract:
Careful process manipulation and adjustment in HVOF spraying is important to optimize the coating, and thus to achieve the desired performance for the application. Gas-particle interactions are commonly monitored by measuring the particle in-flight temperature and velocity. However, for process parameter adjustment, a more detailed understanding of the gas-particle interactions is needed, and for this computational modeling offers an interesting opportunity. Specifically, for a HVOF torch with hydrogen as the fuel gas, the effects of parameter manipulation on coating particle behavior are not well described in the literature. In this work, a computational model is built for the gas flow and coating particle dynamics in HVOF processes (Sulzer Metco Diamond Jet Hybrid), that are fueled with either hydrogen or propylene. The model is compared to experimentally obtained combustion pressure, shock diamond profile, free jet temperature, and particle velocities and surface temperatures. Due to an insignificant mass flow of coating powder, the gas flow is solved without the presence of the powder. Turbulence is taken into account with a variant of the k-epsilon model based on renormalization group theory (RNG), and the combustion is described as a single-step reaction according to an eddy-dissipation model. The computational fluid dynamics (CFD) calculations are conducted with OpenFOAM. Subsequently, the acceleration and heating of individual coating particles are modeled in a

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