Experimental evaluation of thermal stress on the surface of butterfly specimen through irreversible colour change of thermal paint

Abstract

Gas Turbines have been used effectively and extensively in jet propulsion and the sectors of electricity production. The flame produced due to combustion of air & fuel propagates through the gas turbine’s parts. As the hot combustible gases flow through these components, high thermal stresses are imposed on these components. The material life of the individual elements of the gas turbine system depends on its operating temperature and thermal stress. To achieve higher efficiency, the operating temperature may be increased to a certain level. Temperature (or) thermal profiling of the engine components is mandatory to make the engine design reliable. Thermal paint used for temperature profiling of hot surfaces is estimated to be the structured method even after removing the heat source. The present research concentrates on the investigations on the evaluation of thermal stress induced on a hot specimen through the application of thermal paint. A butterfly specimen made of Mild Steel has been fabricated and used for the present experimental investigations. The current work also concentrates on the variation in the surface temperature of the specimen based on the heat input using the butterfly specimen. The colour change on the surface of the specimen has been related to temperature using the RGB values of colour through MATLAB’s fuzzy logic. The results of the experimental investigation prove that the usage of thermal paint reveals the exact deal of stress developed thermally on the surface of the specimen based on the colour change.