Thermal analysis in a film cooling hole with thermal barrier coating

The thickening of tolerable thermal barrier coatings (TBC) at each main hot flow temperature with a film cooling system of normal injection was examined. The thermal analysis was performed using a commercial code, ANSYS Workbench-11 to calculate the thermal stress. The mapped grid was selected for the mesh construction and the geometry consisted of approximately 30,000 elements. The minimum TBC thickness for various main hot gas flow temperatures was determined by making correlations upon TBC thickness and main hot gas temperature using the response surface method. The maximum material temperature of TBC and substrate as well as the maximum debonding stress were obtained from the correlations at any TBC thickness and main hot gas flow temperature. The results revealed that the thick TBC generates a rise in TBC temperature, but a drop in substrate temperature. The TBC thickness at any main hot gas temperature must be carefully considered because both the thin and thick TBC are weak at debonding stress and thermal cycle respectively.