Morphology and Internal Structure of Soot and Carbon Blacks

Measurements of non-volatile fractions of pollution aerosols with an eight-tube volatility tandem differential mobility analyzer (VTDMA-8)

“…The density of black carbon (elemental carbon, graphitic carbon and other optically absorbing carbon compounds) is believed to be smaller than 2 g cm −3 (Wagner, 1981) and often a value of 1 g cm −3 is used if the black carbon consists of chains of individual spherules (Schultz, 1993;Hitzenberger et al, 1999). Establishing a representative density is not straightforward if the carbonaceous material consists of spheres or agglomerates (Lahaye & Prado, 1981;Ishiguro, Takatori, & Akihama, 1997). Particle densities below 1 g cm −3 are assumed if non-spherical particles are in the form of a u y material (Zier & Goetz, 1982;Samson, Mulholland, & Gentry, 1987).…”

Soot aggregates, superaggregates and gel-like networks in laminar diffusion flames

“…Key physical parameters for soot are its size and morphology which fundamentally govern all the situations above. The current view of soot formation and growth in flames involves a series of steps including fuel thermal decomposition to small radicals (Palmer & Cullis, 1965;Glassman, 1988) that react to form polyaromatic hydrocarbons (D'Anna, D'Alesso, & Minutolo, 1994;Dobbins & Subramaniasivam, 1994;Dobbins, Fletcher, & Chang, 1998;Frenklach, 2002) that subsequently nucleate, coalesce and dehydrogenate to yield roughly spherical, graphitic, primary particles of soot with diameters in the few tens of nanometer range (Lahaye & Prado, 1981). After this, the physical process of three-dimensional diffusion limited cluster aggregation (DLCA) (Meakin, 1999;Oh & Sorensen, 1997) proceeds to make noncoalesced clusters which have a fractal morphology with a universal fractal dimension of D 1.8 (Samson, Mulholland, & Gentry, 1987;Dobbins & Megaridis, 1987;Zhang, Sorensen, Ramer, Olivier, & Merklin, 1988;Sorensen, Cai, & Lu, 1992;Koylu & Faeth, 1992).…”

Combustion fume structure and dynamics. Final report

“…Samson et al [ll] found that Df2 < Df3 for computer-generated clusters even when Df3 < 2. Other simulations have shown that the area-size relations of Table 1 are accurate only for clusters containing more than several thousand primary particles [12]. Thus, substantial corrections to the ideal fractal scaling laws may be required for such small clusters.…”