High-Resolution Thermal Profiling of a Combustor in a Non-Dedicated Test Using Thermal History Coatings

Abstract

The requirement for reduced emissions and the growing demand on gas turbine efficiency are in part met through increasing firing temperatures. However, development budgets leave only limited time for dedicated thermal testing. Consequently, manufacturers are seeking novel temperature measurement technologies to validate new engine designs. This paper will demonstrate how a new temperature mapping technology can be utilized for non-dedicated (multi-cycling) testing while still delivering high-resolution temperature data in a non-dedicated test on a combustor of an industrial gas turbine. Typically, thermocouples used to monitor the temperature during tests can only provide one data point. Colour changing thermal paints are used to deliver measurements over complete surfaces require dedicated testing with short-duration exposure. Thermal History Coatings (THC) present an alternative solution to providing high-density temperature information. This coating permanently changes consistency with the maximum temperature of exposure during test. The maximum temperature profile of the surface can be determined through a customized calibration. Given the complex cooling system of a combustor, the high temperatures and the long-time exposure, this case offers a unique possibility for the testing of the coating under real engine conditions. The coated region covered the external surface of the can. Highly significant is the number of measurement points in excess of 7000 (2x2 mm resolution), which enables advanced analysis. The temperature profile is compared to a CFD-CHT model and thermocouple measurements for the calibration of cooling pre-design methods.