Inhibition of atmospheric-pressure H2/O2/N2 flames by trimethylphosphate over range of equivalence ratio

The effect of equivalence ratio (in the range 1.3-3) and dilution of unburnt gases by nitrogen oil speed and the structure of premixed atmospheric-pressure H(2)/O(2)/N(2) flames without additive and doped with 0.04% of trimethylphosphate ((CH(3)O)(3)PO, TMP) was studied experimentally and by modeling. By comparing modeling and experimental results we validated and refined the mechanism for flame inhibition by organophosphorus compounds. Sensitivity analysis of flame speed to reactions of chain branching and chain termination involving phosphorus-containing species revealed some features of the mechanism for inhibition of hydrogen flames of various equivalence ratio and dilution ratio. It was shown that in hydrogen, in contrast to hydrocarbon flames, reactions of radicals with TMP and organophosphorus products of its destruction play important role. The sensitivity analysis revealed the ratio of rates of chain termination reactions involving phosphorus-containing species to chain branching reaction to increase with rising of equivalence ratio and dilution of unburnt gases. Therefore. the inhibition effectiveness of H(2)/O(2)/N(2) flames expressed as a relative decrease of burning velocity rises in the range of equivalence ratio from 1.1 to 3 (in contrast to hydrocarbon flames) and with dilution of unburnt gases. (c) 2009 The Combustion Institute. Published by Elsevier Inc. All rights reserved.