Experimental investigation in rich premixed acetylene flames

Four low pressure premixed acetylene-oxygen-argon flames with equivalence ratio (phi) of 1.00-1.50-2.00 and 2.25 have been investigated. The initial percentage of O-2 has been kept identical in all flames to facilitate comparisons between flames. Signal intensity profiles of stable, atomic and radical species were measured by using mass spectrometry coupled with molecular beam sampling. Absolute concentrations have been obtained by an appropriate calibration and by measuring the corresponding temperature profiles in each individual flames by means a PtRh6%/PtRh30% thermocouple. An increase of the maximum mole fractions Of C3H3, C4H2, C4H4, C4H6, C6H2, C6H4 and C6H6 with the equivalence ratio is demonstrated. Rate coefficients of consumption reactions of acetylene with oxygen atoms and hydroxyl radicals have been deduced and compared with the literature data. C2H2 + O --> Products k(3) = (4.27 +/- 2.13) x 10(14) exp(-3331/T) cm(3)mol(-1)s(-1) C2H2 + OH --> CH3 + CO k(4a) = (4.0 +/- 1.6) x 10(13) exp(-6590/T) cm(3)mol(-1)s(-1) Rate coefficients of reactions of H atoms with C2H2, C4H2, C4H4 and C6H2 have been determined around 1500 K: C2H6 + H --> Products k(5) = 1.78 x 10(11) cm(3) mol(-1)s(-1) C4H2 + H Products --> k(8) = 4.10 x 10(11) cm(3) mol(-1)s(-1) C4H4 + H --> Products k(9) = 1.11 x 10(12) cm(3)mol(-1)s(-1) C6H2 + H --> Products k(10) = 1.62 x 10(12) cm(3)mol(-1)s(-1) (C) 2004 Elsevier Inc. All rights reserved