Self-shadow effect during multi-angle deposition of semi-molten dust on high-temperature TBC surface

Thermal barrier coating (TBC) enables higher operating temperatures in gas turbines, making airborne dust particles more prone to depositing on the TBC surface. While low-melt-point dust particles fully melt and infiltrate the TBC, reducing strain tolerance and leading to failure, the high-melt-point dust particles partially melt and deposit on the TBC, causing surface overheating by altering surface roughness and disrupting flow. Current studies have shown that the curved geometry of engine blades causes dust particles to deposit at different angles, affecting deposition structure and surface morphology. This study simulated the deposition of semi-molten dust particles on TBC surfaces using a high-temperature flame deposition system. Numerical simulation was combined with dust deposition experiments to demonstrate the semi-molten dust gap deposition structure significantly depends on the deposition angle. Experiments revealed the gap deposition structure attributed to the self-shadowing effect, which was quantified using mathematical and numerical methods to calculate the hard-to-deposit areas. These findings provide a more reliable foundation for understanding the potential hazards of semi-molten dust in turbine engines and offer new insights for mitigating the detrimental effects of dust deposition.