Premixed carbon monoxide-nitrous oxide-hydrogen flames: Measured and calculated burning velocities with and without Fe(CO)(5)

The burning velocity of premixed carbon monoxide-nitrous oxide flames (back ground water levels of 5 to 15 ppm) has been determined experimentally for a range of fuel-oxidizer equivalence ratio phi from 0.6 to 3.0, with added nitrogen up to a mole fraction of X-N2 = 0.25, and with hydrogen added up t o X-H2 = 0.005. Numerical modeling of the flames based on a recently develo ped kinetic mechanism predicts the burning velocity reasonably well, and in dicates that the direct reaction of CO with N2O is the most important react ion for CO and N2O consumption for values of X-H2 less than or equal to 0.0 014. The calculations show that a background H-2 level of 10 ppm increases the burning velocity by only about 1% compared to the bone-dry case. Additi on of iron pentacarbonyl, Fe(CO)(5), a powerful flame inhibitor in hydrocar bon-air flames, increases the burning velocity of the CO-N2O flames signifi cantly. The promotion is believed to be due to the iron-catalyzed gas-phase reaction of N2O with CO, via N2O + M = N-2 + MO and CO + MO = CO2 + M, whe re M is Fe, FeO, or FeOH. Published by Elsevier Science Inc.