Shock tube measurements of branched alkane ignition times and OH concentration time histories

Abstract

AbstractIgnition times and hydroxyl (OH) radical concentration time histories were measured behind reflected shock waves during the oxidation of three branched alkanes: iso‐butane (2‐methylpropane), iso‐pentane (2‐methylbutane), and iso‐octane (2,2,4‐trimethylpentane). Initial reflected shock conditions ranged from 1177 to 2009 K and 1.10 to 12.58 atm with dilute fuel/O2/Ar mixtures varying in fuel concentration from 100 ppm to 1.25% and in equivalence ratio from 0.25 to 2. Ignition times were measured using endwall CH emission and OH concentrations were measured using narrow‐linewidth ring‐dye laser absorption of the R1(5) line of the OH A‐X (0,0) band at 306.7 nm. The ignition times and OH concentration time histories were compared to modeled predictions of seven branched alkane oxidation mechanisms currently available in the literature and the implications of these comparisons are discussed. These data provide a unique database for the validation of detailed hydrocarbon oxidation mechanisms of propulsion related fuels. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 36: 67–78 2004