Experiments of acoustic pyrometry in power plant boilers

The paper presents an acoustic pyrometry method for the reconstruction of temperature maps inside power plant boilers. It is based on measuring times-of-flight of acoustic waves aiong a number of straight paths in a cross-section of the boiler; via an integral relationship, these times depend on the temperature of the gaseous medium along the paths. On this basis, 2D temperature maps can be reconstructed using suitable tomographic inversion techniques. Two such techniques, with examples of temperature reconstructions from experimental data, are presented. The results appear fairly satisfactory, considering the small data sets that it was possible to acquire in the tested boilers.