MEASUREMENT OF SOOT VOLUME FRACTION AND TEMPERATURE FIELDS OF AN AXISYMMETRIC FLAME USING AN ITERATIVE IMAGE RECREATION METHOD

A method to recreate an image of a virtual sooting flame is presented. To do this, a spatial field of soot volume fraction and temperature is needed. It is assumed that the dominant emission mechanism is grey body radiation and that the primary soot particles are below the Rayleigh limit. If the spectral and intensity responses of a camera are known, it is possible to recreate the image of the flame by integration of the radiation along the line of sight. The measurement of the soot volume fraction and the temperature is done iteratively – a first guess is proposed, an image is constructed and compared to the real image. If images are different, the soot volume fraction and temperature fields are adjusted and the process is repeated. The iteration procedure is explained. The method is tested on a co-flowing laminar diffusion flame of ethylene and air. The results are compared to other, more established methods. It appears that the proposed method reproduces well soot volume fractions, while there is a noticeable disparity in the temperature results.