Numerical Study of the Inhibition of Premixed and Diffusion Flames by Iron Pentacarbonyl.
Numerical Study of the Inhibition of Premixed and
Diffusion Flames by Iron Pentacarbonyl.
Rumminger, M. D.; Reinelt, D.; Babushok, V. I.;
Linteris, G. T.
Combustion and Flame, Vol. 116, 207-219, 1999.
chemical inhibition; flame chemistry
Iron pentacarbonyl (Fe(CO)5) is an extremely efficient
flame inhibitor, yet its inhibition mechanism has not
been described. The flame-inhibition mechanism of
Fe(CO)5 in premixed and counterflow diffusion flames of
methane, oxygen, and nitrogen is investigated. A
gas-phase inhibition mechanism involving catalytic
removal of H atoms by iron-containing species is
presented. For premixed flames, numerical predictions
of burning velocity are comapred with experimental
measurements at three equivalence ratios (0.0, 1.0, and
1.1) and three oxidizer compositions (0.20, 0.21, and
0.24 oxygen mole fraction in nitrogen). For counterflow
diffusion flames, numerical predictions of extinction
strain rate are compared with experimental results for
addition of inhibitor to the air and fuel stream. The
numerical predictions agree reasonable well with
experimental measurements at low inhibitor mole
fraction, but at higher Fe(CO)5 mole fractions the
simulations overpredict inhibition. The overprediction
is suggested to be due to condensation of
iron-containing compounds since calculated
supersaturation ratios for Fe and FeO are significantly
higher than unity in some regions of the flames. The
results lead to the conclusion that inhibition occurs
primarily by homogeneous gas-phase chemistry.