Soot and velocity mapping and 2D soot sheet dimensions in a buoyant wall-fire

• Published in: Proceedings of the Combustion Institute Vol. 36; no. 2; pp. 3219 - 3226
• Main Authors: Valencia, Andrés, Talbaut, Martine, Yon, Jérôme, Godard, Gilles, Gobin, Carole, Coppalle, Alexis
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 2017; Elsevier
• Subjects: Fluid mechanics; Laser diagnostics; LII; Mechanics; Physics; PIV; Soot; Wall fire; PIV; LII; Soot; Laser diagnostics; Wall fire
• ISSN: 1540-7489; 1873-2704; 1540-7489
• DOI: 10.1016/j.proci.2016.06.142

The study used a vertical porous burner fueled with a CH4/C2H4 mixture burning in quiescent ambient air to measure the soot content of a vertical turbulent wall flame. Soot volume fractions were determined by planar laser induced incandescence (LII). Particle image velocimetry (PIV) was used to measure the vertical velocity of the mean flow. The mean soot volume fraction and vertical velocity values were mapped with a two-dimensional (2D) imaging technique. Soot volume fraction flux was analyzed as a function of height. The results show that, in the top zone of the flame, the soot formation was counterbalanced by oxidation with air. In addition, each instantaneous 2D soot sheet was analyzed to determine two parameters: the soot volume fraction maximum fv,max and the horizontal width δFWHM. For both parameters, average and RMS (root mean square) values were calculated at each height. Except for the bottom zone of the burner, average values varied little with height, whereas RMS values remained persistently high. It is found that, with increasing heights, there exist far from the burner and in the lean side of the flame more and more soot sheets with high values of fv max and δFWHM.