Simultaneous soot temperature and volume fraction measurements in axis-symmetric flames by a two-dimensional modulated absorption/emission technique

Abstract

multaneous soot temperature and volume fraction measurements in axis-symmetric flames by a twodimensional modulated absorption/emission technique. Combustion and Flame, Elsevier, 2015, 162, pp.2705 -2719. <10.1016/j.combustflame.2015 AbstractThe original contribution of the present paper is to present a joint theoretical and experimental approach to implement the modulated absorption/emission technique. Two-dimensional fields of soot temperature and volume fraction can then be measured simultaneously in a reference steady laminar coflow axis-symmetric non-premixed ethylene flame estalished over * Corresponding author Email addresses: guillaume.legros@dalembert.upmc.fr (Guillaume Legros ), wangqianlong212@gmail.com (Qianlong Wang), jerome.bonnety@upmc.fr (Jérôme Bonnety), muhammad.kashif@ucp.edu.pk (Muhammad Kashif), celine.morin@univ-valenciennes.fr (Céline Morin), jean-louis.consalvi@univ-amu.fr (Jean-Louis Consalvi),

Experimental assessment of the sudden-reversal of the oxygen dilution effect on soot production in coflow ethylene flames

“…Furthermore, the use of the upper part of the visible spectrum consolidates the predominance of absorption over scattering by soot particles, knowing that the participat-ing medium is considered as non-scattering in the post-processing. As a result, the selection of λ 1 and λ 2 was proven to enable the simultaneous reconstructions of the soot temperature and volume fraction distributions with acceptable uncertainties [19].…”

“…[19]. This technique provides simultaneous twodimensional maps of soot temperature and volume fraction in the axisymmetric laminar diffusion flames investigated [24,25].…”

“…To further address the sudden-reversal behaviour in soot production of oxygen addition to fuel stream in ethylene diffusion flames, the two-dimensional soot temperature and volume fraction fields are measured in the present paper using the Modulated Absorption/Emission (MAE) technique [19] , at which the sudden-reversal of oxygen addition to soot formation occurs, to the coflow oxidizer stream composition is assessed by replacing different amounts of nitrogen in the air with carbon dioxide.…”

“…Furthermore, following the methodology prescribed by Legros et al [19], confidence regions for soot temperature and volume fraction measurements can be identified according to the local relative levels of κ λ B λ and κ λ . These regions are also delineated here, guaranteeing that the measurements of soot temperature and volume fraction reported hereafter exhibit uncertainty levels lower than ±50 K and ±0.5 ppm, respectively.…”

“…(4) and (1) is discretized at every height z i imaged on a line of pixels, leading to a system of linear equations that is solved for (κ λ ) ij and (κ λ B λ ) ij , respectively, at the locations r j along the line. As every set of equations is shown to be ill-conditioned, a Tikhonov regularization is used to stabilize the deconvolution process [19].…”