Spectral Extinction Coefficients of Soot Aggregates From Turbulent Diffusion Flames.
Spectral Extinction Coefficients of Soot Aggregates From
Turbulent Diffusion Flames.
Koylu, U. O.; Faeth, G. M.
Combustion Institute/Eastern States Section. Chemical
and Physical Processes in Combustion. Proceedings.
Fall Technical Meeting, 1995. October 16-18, 1995,
Worcester, MA, 211-214 pp, 1995.
Sponsor:Air Force Office of Scientific Research, Washington, DC
combustion; soot; aggregates; turbulent flames;
diffusion flames; extinction; luminous flames; soot
Accurate knowledge of the spectral variation of the
refractive indices of soot is necessary in order to
estimate continuum radiation from luminous flames and to
develop in-situ optical techniques for measuring soot
properties. However, there are fairly large variations
among the soot refractive indices reported in the
literature, implying uncertainties about which values
should be used in a particular application, see example,
Tien and Lee, Chang and Charalampopoulos, and references
cited therein for a complete discussion. Moreover,
results regarding the effects of fuel type (H/C ratio)
on soot refractive indices are also contradictory.
Early work of Dalzell and Sarofim, and Lee and Tien
suggested that soot refractive indices were relatively
insensitive to fuel type. On the other hand, later work
of Habib and Vervisch, and Charalampopoulos et al
indicated significant effects of fuel type on soot
refractive indices. However, Sivathanu et al recently
reported that their measurements were most consistent
with the values reported by Dalzell and Sarofim, while
finding only a weak dependence of fuel type on soot
refractive indices. In view of these observations, the
main objective of the present study was to evaluate the
capabilities of the soot refractive indices reported in
the literature to treat the spectral extinction
properties of soot aggregates, and to investigate the
effect of fuel type on refractive indices.