Comparison of Different Two-Equation Turbulence Models for Dynamic Effect in HVOF Thermal Spray Process Modeling

High velocity oxygen-fuel (HVOF) thermal spraying is an advanced

manufacturing process that adds or improves functionality to component surfaces.HVOF process essentially provides a supersonic flame and deposits semi-molten powder particles to component surfaces in well-controlled dynamic environment. Due to the high-energy flame and particles’ impacting, substrate surface behavior during the process essentially affect the coating quality. Thus, predicting the dynamic performance of substrates is crucial. To achieve the goal of predicting

HVOF process outcome accurately, this paper proposes an iterative coupling method to obtain the substrate dynamic performance with the consideration of the spray torch trajectory. The renormalization group (RNG) and the realizable k-ε  turbulence models were separately used in the reported research to test the simulation results with those two different models on the dynamic behavior of the substrate. Temperature field simulations of the substrate were selected for the comparison purpose under two sets of operation conditions with different scanning

velocities. Through the evaluations with experimental measurements, it can be concluded that the RNG k-ε turbulence model generates more accurate dynamic performance results than the realizable k-ε turbulence model.