Time-Resolved Soot Particulates in Diesel Spray Combustion

Abstract

Experiments have been made to study the soot particulates formed at different stages of combustion of a simulated diesel spray by applying a newly developed laboratory combustor in which the following two essential characteristics of diesel spray combustion are reproduced: intermittency and autoignition. The combustor is designed so that the fuel is injected by using a diesel fuel injection system into a steadily flowing high temperature air stream resulting in autoignition and combustion. Soot particulates have been collected at different stages of combustion by applying an inert gas quenching technique. The mass concentration, diameter, number and carbon-to-hydrogen ratio of soot particulates, oxygen concentration and temperature in the flame as a function of the time from the start of fuel injection have been obtained. Mutagenic activity of the time-resolved soot particulates has been determined by using the bacterial mutagenesis test. Thus, some factors affecting time-resolved characteristics of soot particulates have been studied. Theoretical analysis is also made of the physical mechanism for soot particulates formation.