Ultrafine particles from combustion sources: approaches to what we want to know

Abstract

Soot formation and oxidation will be analysed with respect to the most important processes, namely particle inception, coagulation and surface growth. Time–scales of surface growth are estimated for premixed and diffusion flames and compared with time–scales for coagulation. It turns out that characteristic time–scales for soot formation and coagulation are similar and about one order of magnitude larger than the characteristic time–scales for combustion reactions and much smaller than the time–scales of molecular transport.