Recovery of temperature and species concentration profiles in flames usinglow-resolution infrared spectroscopy

The temperature and species distributions in semi-transparent gaseous axisy mmetric objects are retrieved by carrying out the inversion of their direct ional low-resolution spectral transmission and/or spectral emission in the infrared by using methods based on the solution of the radiative transfer e quation. The validity domains of the hypothesis on which the low resolution inversion methods are based are discussed by comparison with the correspon ding exact radiative properties generated by line-by-line descriptions. A p ropane-air laminar premixed flame is experimentally studied. The infrared d ata are collected for the (v(3)) band of CO2, either bg a directional scann ing (at a fixed frequency) or by a frequency scanning (in a fixed direction ). Depending on the data acquisition methods, two different reconstruction techniques are used For spatial scanning, a generalized Abel transformation or the regularized Murio's method, is utilized. For spectral scanning the recovered results are carried out by the Chahine-Smith method. For both tec hniques, profile reconstructions are worked out accounting for a spectral d ata bank based on the narrow statistical band model. Finally, thermal and C O2 concentration mappings of the premixed flame are presented.