Effects of thermal barrier coating thickness and surface roughness on cooling performance sensitivity of a turbine blade

Abstract

In this study, the conjugate heat transfer method is used to research the impact of the thermal barrier coating thickness (0–300 μm) and surface roughness (Ra = 0–30 μm) on the cooling characteristics of the high-pressure turbine blade. A physical thin-walled structure is applied to simulate the TBC on the turbine blade surface. The results indicate that the temperature distribution on the coated metal surface is more uniform. With an increase in coating thickness, the heat flux of the blade surface decreases, reaching a maximum of 106W/m2 at the leading edge. Furthermore, leading-edge temperature is the most sensitive to changes in coating thickness, and the pressure surface is the least sensitive. The overall cooling effectiveness is less sensitive to changes in the roughness after coating. Increasing the surface roughness, the heat flux reduces at the leading edge and increases at other places. The range of the overall cooling effectiveness rate of the blade rises, and the sensitivity of the overall cooling effectiveness to the coating thickness increases. When Ra reaches 20 μm, the insulation effect with different coating thickness remains unaffected.

Keywords

• Thermal barrier coating thickness
• Surface roughness
• Conjugate heat transfer
• Cooling performance sensitivity
• Turbine blades