DME Effect on Soot Formation in Acetylene/Air Flames

The paper presents the results of an experimental and numerical study of the DME addition effect on the soot particle formation and growth in acetylene/air flames. Soot particles produced in a flat, laminar, premixed acetylene/air flame with the content of 0 to 15.4% of DME were studied in-situ by the laser extinction (LE) method and ex-situ by transmission electron microscopy (TEM). The method of laser extinction at wavelengths from 405 to 850 nm allowed to obtain the data on the volume fraction of the condensed phase in the flame, as well as on their optical band gap. The mean soot particle size was extracted from an analysis of TEM photos. Numerical modeling was carried out using a modern kinetic mechanism of pyrolysis and oxidation of hydrocarbons, including a sectional model of the soot particle growth. As a result, it is shown that DME additives lead to a decrease in the soot yield, a decrease in the average size of soot particles, and a change of their optical and electrical conductivity properties.