Morphology of particles generated during hydrocarbons or biomass combustion is fundamental as data for characterizing the optical and aerodynamic behaviour of these particles. The fractal nature of soot particles is well known since the works of Jullien and Botet (1987). Nevertheless, the determination of the fractal morphology of this aggregates is based on direct analysis of transmission electronic microscopy (TEM) micrograph (Köylü et al., 1995; Sorensen and Feke, 1996; Brasil et al., 2000) which represents a long and tiresome work. We propose in this work to use the method introduced by Kelly and McMurry (1992) and based on serial analysis of electrical mobility and aerodynamic diameters of soot aggregates. This method has been recently used by VanGulijk et al. (2004) and Park et al. (2004), and seems to bring morphological information systematically higher than the TEM analysis. In this study we will detail the TEM analysis method and the theoretical approach associated to the serial method of Kelly and McMurry (1992). We will also present the experimental setup used and the results obtained for aggregates generated during the combustion of acetylene (C2H2), toluene (C7H8) and PolyMethyl Methacrylate (PMMA, C5H8O2). These results will be compared to TEM analysis results, and discrepancies will be analysed and explained in detail. We will finally concluded on advantages and disadvantages of each method and also on potential of these approaches. The link will be thus established out with the determination of the effective density of the soot aggregates, which is presented in work of Ouf et al. (2005a).
(1) Institut de Radioprotection et de Sûreté Nucléaire/ Service d’Etudes et de Recherches en Aérodispersion des polluants et en Confinement, B.P. 68, 91192 Gif-sur-Yvette Cedex, France
(2) Centre d’Etudes et de Recherche en Thermique, Environnement et Système, Université Paris XII, 61 av. du Général De Gaulle, 94010 Créteil Cedex , France