Bimodal Particle Size Distributions and Morphology of Soot in a Laminar Premixed EthyleneFlame

摘要

In the present study, soot PSDFs were investigated in a premixed ethylene-oxygen-argon flame at equivalenceratios of 2.50 by online probe sampling and Scanning Mobility Particle Sizer (SMPS) analysis. Samples werealso extracted by the rapid insertion technique followed by TEM analyses. For the current heavier sooting flame,the PSDF consists of two lognormal distributions, one that peaks around 6 nm in particle diameter and the other atparticle diameters > 20 nm. TEM analysis shows that the small-size part of the PSDF is associated with nearlyspherical particles, whereas the second, larger-size modal contains mainly aggregates of low fractal dimensions.Soot samples under TEM appear to be liquid like and far from being carbonized. The implication of the currentexperiments on soot mass and size growth will be discussed.