Knowledge on the local value of reducing and oxidizing (redox) atmospheres in flames is among the most important issues to be desired by combustion engineers. In this study, the spatial distribution of a redox atmosphere in flames has been measured experimentally by the chemical seeding/laser-induced fluorescence (CS/LIF) technique. A solution of iron was sprayed into a premixed propane-air flame supported on a slot burner. The LIF intensity of FeO band was compared to that of a Fe line to estimate the experimentally determined degree of atomization in the reaction $FeO→Fe+O$. The flame temperature profile was determined as a rotational temperature and was obtained by comparing the LIF (laser-induced fluorescence) intensities of OH rotational lines. The degree of atomization was theoretically calculated on the basis that simple thermal dissociation takes place in the reaction. The redox atmosphere, or a redox index, is defined as the ratio of the experimentally determined to theoretically calculated degrees of atomization. Two-dimensional distributions or profiles of the excitation temperature, experimentally determined degree of atomization, and redox index have been measured using a charge coupled device (CCD) camera fitted with an optical bandpass filter and the associated signal processing using a computer. This method has been successfully applied to quantitatively illustrate the local atmosphere and profile of the redox atmosphere in flames.

1.
Kubota
,
M.
,
Kitagawa
,
K.
,
Arai
,
N.
, and
Gupta
,
A. K.
, 2002, “
Profiling of Redox Index During Combustion to Monitor C/C Composite Degradation in Flames
,”
J. Propul. Power
0748-4658,
18
(
2
), pp.
372
375
.
2.
Kitagawa
,
K.
,
Ide
,
Y.
, and
Takeuchi
,
T.
, 1980, “
Spectroscopic Determination of Atomization Efficiency (CuCl→Cu+Cl) in an Air-Acetylene Flame
,”
Anal. Chim. Acta
0003-2670, Vol.
113
, pp.
21
32
.
3.
Cattolica
,
R.
, 1981, “
OH Rotational Temperature From Two-Line Laser Excited Florescence
,”
Appl. Opt.
0003-6935,
20
, pp.
1156
1166
.
4.
De Galan
,
L.
,
Smith
,
R.
, and
Winefordner
,
J. D.
, 1976, “
The Electric Partition Functions of Atoms and Ions Between 1500°K and 7000°K
,”
Spectrochim. Acta, Part B
0584-8547,
23B
, pp.
521
525
.
5.
Herzberg
,
G.
, 1950,
Molecular Spectra and Molecular Structure I. Spectra of Diatomic Molecules
,
VanNostrand Reinhold
,
Princeton
.
6.
Moore
,
W. J.
, 1956,
Physical Chemistry
, 2nd ed.,
Lowe & Brydone
,
London
.
7.
Corliss
,
C. H.
, and
Bozmann
,
W. R.
, 1994,
NBS Monograph 53
,
U.S. Government Printing Office
,
Washington
, DC.