E. S. Davis, S. R. Duncan, P. S. Grant, University of Oxford, Oxford, United Kingdom
As the initial step of a process control design for a substrate surface temperature control solution for Vacuum Plasma Spraying (VPS), the distribution of heat transfer coefficient between impinging plasma gases and the substrate coating surface is required. An embedded calorimeter approach was applied to measure the distribution of the convective heat transfer coefficient over the surface of a substrate and the resulting distributions have been compared with empirical correlations and CFD model predictions of the plasma jet/substrate interaction as a function of VPS process parameters. The use of these data in a practical system for the real-time control of coating surface temperature will also be discussed.
Summary: This paper presents a model of the distribution of the heat transfer coefficient between substrate and impinging plasma gases during vacuum plasma spraying. It is then shown how this model is used as the basis for a real-time substrate temperature control system.