Effects of Metal Additives on Soot Precursors and Particulates in a C2H4/O2/N2/ArPremixed Flame

摘要

Parameters which characterize soot precursor and particulate species in aC2H4/O2/N2/Ar premixed flame have been measured both with and without alkali and alkaline earth salts present as fuel additives. The principal experimental techniques which were used include Mie scattering and optical extinction for particulate size, number density and volume fraction, and gas chromatographic analysis of quartz probe collected samples for the determination of precursor concentrations. Other critical parameters such as flame temperature and metal species concentrations were addressed as well. Temperature was determined from the Wien equation using measured values of the flame's absorptivity and brightness. Species concentrations were estimated from analytical expressions known to be reliable for premixed flames. Data are presented which give the effects of the above metals on the particulates for three well-defined but different ethylene flames. The efficiency of a given metal is shown to be dependent almost exclusively on temperature and the metal atom's ionization potential; the higher the temperature and the lower the ionization potential, the greater is the soot removal. (Author)