Dynamic evolution of melting particle deposition and overall cooling effectiveness on a film-cooled flat plate

Molten particle deposition and film cooling performance degradation in gas turbines are highly coupled and dynamic processes. The previous studies have underestimated the coupling effects between the two processes, lacking in-depth research on their dynamic evolution processes. In this study, a prediction workflow for molten particle deposition was developed based on a high-temperature deposition model and conjugate mesh morphing technology. The characteristics of particle deposition and the evolution of overall cooling effectiveness on a film-cooled flat plate were analyzed both qualitatively and quantitatively. The results indicate that deposition on the film-cooled surface is concentrated upstream of the film holes and along the sides of the cooling film. The deposition efficiency downstream of the film holes increases with the blowing ratio but decreases with increasing equivalent engine time. Over a prolonged period, the deposition efficiency inside the cooling holes decreases with a higher blowing ratio but increases with longer equivalent operating time. At all blowing ratios, the area-averaged overall cooling effectiveness initially increases by 11.3 %–20.2 % with deposition levels, then decreases by 15.9 %–25.5 % from its peak and stabilizes. Cooling performance initially improves with deposition-induced thermal insulation but deteriorates due to cooling hole blockage at later deposition stages. Finally, the correlation describing the evolution of deposition efficiency and area-averaged overall cooling effectiveness are provided. These results offer valuable guidance for the engineering application of rapid prediction methods for particle deposition and cooling performance degradation in gas turbines.