In order to enhance turboshaft lifespan and increase thermal efficiency, aeronautical manufacturers have to optimize the temperature of engine components in operation. Dedicated combustion tests are undertaken and specific techniques are developed to measure surface temperatures. Thermal paints have been used for several years, associated with skilled operator observations, as a valuable means to get peak temperature profiles. This article describes major advances in the analysis process based on color to temperature supervised classification and digitization of the outer shape of the components in order to get 3D temperature maps. A non-contact scanner enables to acquire both a color image and a 3D mesh of the component. The color image is processed with a classification algorithm to give a temperature image. Different colorimetric distances are tested to compare each pixel to the database and find the best matching temperature, which is then associated to a node of the 3D mesh. The relevance of the method is to increase temperature resolution and robustness and to allow more reliable comparisons between numerical simulation and bench test measurement. This system is currently implemented in the engine development process at Turbomeca.
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