Numerical prediction of thermal insulation performance and stress distribution of thermal barrier coatings coated on a turbine vane

Abstract

Understanding the thermal insulation performance and thermal stress of thermal barrier coating (TBC) coupled with internal cooling and film cooling plays a key role in designing and predicting the failure of TBC. In this work, A one-dimensional theoretical model is presented to analyze the trends of performance of TBC with respect to various parameters. Based on the fluid-solid coupling method, a three-dimensional (3D) finite element model of a guide vane coated with TBC is performed to evaluate the thermal insulation effectiveness and thermal stress of TBC. Furthermore, the effect of film hole geometries on the thermal insulation performance and thermal stress distribution of TBC are investigated. It is found the thermal insulation effectiveness decreases with the increase of film cooling effectiveness but increases with external/internal convective heat transfer coefficients. According to the thermal stress results, the dangerous regions of TBCs are predicted. Stress concentration occurs at the upstream position of film hole. Compared with the round and fan holes, the thermal stress of TBC with trench hole is lowest. Comprehensive consideration the thermal insulation performance and stress distribution of TBC with different film hole geometries, the trench hole is a better design for a longtime service of TBC.