Two-dimensional soot

Large soot aggregates (ca. 100 mum) in acetylene-air diffusion flames are physically flat and have a fractal dimension of D = 1.40 +/- 0.04 consistent with simulations of two-dimensional diffusion-limited cluster aggregation. This occurs because the soot is constrained to a cylindrical annular flame front with a radial thickness that appears thin relative to the increasing dimensions of the soot aggregates, thus confining them to a two-dimensional space during aggregation.