Validation of Thermal History Coating Technology on Two Stage-One Turbine Blades

Abstract

Small and midsize gas turbines for distributed power generation have been widely used in recent years, with designers constantly seeking to improve efficiency by increasing operating temperatures. Therefore, accurate thermal mapping is now more critical than ever for validating new designs, but also very challenging in such a dynamic environment as a gas turbine. A novel advanced offline temperature mapping technology has been developed called thermal history coating (THC). Thermal History technology has distinct advantages including wide temperature measurement range (150 °C to >1600 °C), high durability, high-temperature resolution, single or multicycle operation, high spatial resolution (thousands of measurement points per component), and fully digitized computer-aided design (CAD) compatible data. Additionally, THC materials are REACH-compliant and can be used for both moving and stationary components. High-resolution thermal maps of the surface of three-dimensional (3D) CAD components can be delivered at the end of the process. For the first time ever this paper directly compares Thermal History technology with other methods such as Type-K sheathed thermocouples, uniform crystal temperature sensors (UCTS), and pyrometry on two stage-1 blades of a midsize Kawasaki gas turbine engine test. Temperature data obtained from the different temperature methods were compared qualitatively and quantitatively. Measurement data were also compared with the conjugate heat transfer (CHT) model for the particular internal cooling design of these blades. Further, the application of the THC on two identical blades allowed a direct comparison of component-to-component variations and indicated excellent repeatability of the THC data.