12th European Conference on Turbomachinery Fluid dynamics & Thermodynamics
The measurement of surface temperatures of hot-gas path components of gas turbines under operating conditions provides a considerable challenge because the complexity of measurements under the prevailing conditions is substantial. The results from temperature measurements from an engine test using Thermal History Paint (THP) are presented here. The sensor material in the THP is an oxide ceramic which is doped with lanthanide ions to make the material luminescent. The properties of the luminescence depend on the temperature of exposure. The paper describes the first application of this technology in an extended, rather than dedicated, engine test in which components in both the hot gas path and the secondary air system were coated with THP. During the test campaign the engine components operated below maximum temperature for extended periods of time, which required a novel approach to the calibration of the paint. An overview over the correspondence between the temperatures measured with the THP, thermal paints and CFD calculations is provided for a sideplate and turbine blade. There is very good correlation between the results of the different methods. For the sideplate, the temperature measured with the THP was within 10K of the CFD calculation. Furthermore, the THP exhibited only minor erosion damage after over 50 hours of engine testing. The high durability and measurement accuracy demonstrate the feasibility of using the THP in extended engine tests.