Development of thermal gradient prediction method for thermal barrier coating

Abstract

Thermal barrier coatings (TBC) protect the components of gas turbines from severe environments by reducing the surface temperature of the substrate. Therefore, an accurate prediction of the temperature gradient (temperature drop) in TBC is an important issue when estimating the exact life of the components. Material properties of bulk ceramic are often used for the analysis. However, Bulk materials do not have the same material properties as thin ceramic layers due to differences in processing and micro structure. Bulk materials also have different interfacial properties since the ceramic is sprayed on different materials with highly conductivity. Therefore, it is necessary to develop a thermal barrier performance test method using a TBC applied to real gas turbine. In this study, a thermal barrier performance test method was developed using the TBC applied to real gas turbine. The thermal gradient of a real gas turbine was analyzed by FEA, using measured conductive heat transfer coefficients. A simple equation that can predict thermal gradient conditions of the components in a gas turbine from measured temperature of the test is proposed. Finally, Thermal barrier performance tests on various TBCs were conducted. The test method was verified by comparing the tested data with reference data.