Generation of CO and Smoke During Underventilated Combustion.
Generation of CO and Smoke During Underventilated
Leonard, S.; Mulholland, G. W.; Puri, R.; Santoro, R. J.
Combustion and Flame, Vol. 98, 20-34, 1994.
combustion; carbon monoxide; smoke; ethene; flame
research; laminar flames; methane; smoke yield; global
equivalence ratio; underventilated combustion
The CO and smoke yields observed for underventilated
laminar diffusion flames are presented for methane and
ethene for global equivalence ratio phi over the range
0.5 to 4.0. A Burke-Schumann type burner with fuel in
the center tube and air in the annular region was used.
The peak CO yields for methane and ethene, 0.37 and 0.47
respectively, are at least a factor of 100 greater than
for overventilated burning. The ratio of CO/CO2 versus
phi for the methane flame is compared with local
measurements of this ratio for both overventilated and
underventilated laminar diffusion flames and with the
results for turbulent natural gas flames quenched in an
upper layer. The peak smoke yields for methane at a
flow rate of 10 cm3/s and for ethene at a fuel flow rate
of 6.4 cm3/s are 0.01 and 0.05, and ethene are 0.01 and
0.05, respectively, compared with yields of 0 and 0.028
for the overventilated case. The proportionality
between smoke yield and CO yield observed for
overventilated burning for a wide range of fuels is
found not to be valid for the underventilated case. The
chemical makeup and structure of the smoke produced at
high equivalence ratio is qualitatively different from
smoke produced under overventilated conditions; the
smoke is mainly organic rather than graphitic and it has
an agglutinated structure rather than an agglomerate
structure with distinct primary spheres usually observed
in overventilated burning.