Physical Aspects of Nucleation and Growth of Soot Particles

Abstract

In order to shed light on the physical mechanisms of soot formation, two different soot producing systems were investigated: thermal decomposition of benzene and methane and laminar premixed flat flames. The experimental techniques used to measure the size and number density of soot particles were either electron microscopy or laser light scattering and absorption. In some experiments both techniques were used in a complementary fashion. Soot consists essentially of agglomerates of a number of small spherical carbon particles. Electron micrographs obtained from collected soot yield a reliable size distribution and number concentration of the individual spherical elements, providing information on particle nucleation, coalescent coagulation and surface growth. The in situ optical methods, on the other hand, see only the true agglomerate, providing complementary information on particle agglomeration.