OH concentration time histories in n-alkane oxidation

OH radical concentration time histories were measured behind reflected shoc ks in the oxidation of four n-alkanes: propane, n-butane, n-heptane, and n- decane. Initial reflected shock conditions of these measurements were 1357- 1784 K, 2.02-3.80 atm, with fuel concentrations of 300-2000 ppm, and equiva lence ratios from 0.8 to 1.2. OH concentrations were measured using narrow- linewidth ring-dye laser absorption of the R-1 (5) line of the A-X (0,0) tr ansition at 306.5 nm. These concentration time-history measurements were co mpared to the modeled predictions of eight large n-alkane oxidation mechani sms currently available in the literature and the kinetic implications of t hese measurements are discussed. These data, in conjunction with recent mea surements of n-alkane ignition times and ethylene yields in n-alkane pyroly sis experiments, also performed in this laboratory, provide a unique databa se of species concentration time histories for n-alkane mechanism validatio n. (C) 2001 John Wiley & Sons, Inc.