We report the observation of a novel phase of soot in an acetylene/air laminar diffusion flame. As was measured by a small-angle light scattering apparatus, the phase consists of about 10-μm superaggregates with a fractal dimension of D ≃ 2.6. This phase coexists with submicrometer D ≃ 1.8 soot fractal aggregates typical for most flames. Both percolation and shear-induced restructuring are considered as possible mechanisms of formation for those superaggregates.

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