A. Elbakali et al., MEASUREMENT OF SOOT VOLUME FRACTION AND GASEOUS SPECIES CONCENTRATIONS IN PREMIXED N-HEPTANE AND ISOOCTANE FLAMES, Journal de chimie physique et de physico-chimie biologique, 94(9), 1997, pp. 1659-1673
The main objective of this work was to correlate in n-heptane and iso-
octane flames the soot volume fraction and the mole fraction of benzen
e and its precursors. Both series of measurements were performed in pr
emixed laminar flames stabilised at atmospheric pressure on a flat fla
me burner. Soot volume fraction profiles were derived from attenuation
of a 670 nm Helium-Neon laser beam. Species concentration profiles we
re obtained by gas Chromatography analysis of samples withdrawn with f
ine quartz microprobes. Species analysed (benzene, acetylene, allene,
propyne, vinylacetylene) exhibit a maximum prior the onset oi. soot fo
rmation. Additional gas species measurements were performed in the soo
ting region. A wide range of equivalence ratio was investigated : from
1.5 to 2.24 for n-heptane and from 1.5 to 2.16 for isooctane flames.
Results show that the soot volume fraction is strongly correlated to t
he local acetylene concentration. On the other hand, no correlation is
observed with benzene since for a given equivalence ratio, the soot c
oncentrations measured for each fuel are almost similar while benzene
concentration is markedly higher in the isooctane flames.