Reaction mechanism of propane oxidation

The ignition of propane-oxygen-argon mixtures was observed behind reflected shock waves at temperatures from 1380 to 1890 K and pressures from 2.6 to 4.2 atm in a 7.6-cm-i.d. shock tube. The test gas compositions as volume percent in argon were: (&phis;---equivalence ratio) (1) Mixture A---0.15%C 3H8 + 0.84%O2 (&phis; = 0.9); (2) Mixture B---0.20%C3H8 + 1.00%O2 (&phis; = 1.0); (3) Mixture C---0.15%C3H8 + 1.00%O2 (&phis; = 0.76); (4) Mixture D---0.20%C3H8 + 1.33%O2 (&phis; = 0.76). An argon-ion-laser pumped cw ring dye laser was used to observe OH in absorption at 310 nm. Ignition delay time were defined as the time between reflected shock arrival at the laser beam and the time at which the rate of OH absorption rise reached its maximum. All experimental ignition delay times were obtained from OH absorption profiles.;The chemical reaction mechanism developed to describe high temperature propane ignition consists of the C1 and C2 submechanism in GRI-MECH 2.11 supplemented by a C3 submechanism assembled from critical study of the literature. The modeling calculations assumed adiabatic constant-density reaction starting at the conditions behind the reflected shock wave computed from the measured incident shock speed. Ignition delay times served as the primary modeling target. Detailed sensitivity analyses were carried out to identify the sensitive reactions. The rate coefficient for the most sensitive C3 reaction, C3H8 → CH3 + C2H5, was adjusted to match the experiments. Propyne and allene oxidation were studied also. The rate coefficient of the most sensitive reaction for C3H4 ignition delay, C 3H3 + O2 → C2H2O + HCO, was adjusted in order to fit the experimental data. The experimental data of this study are well reproduced by computer simulations done using the mechanism.;Validation of the mechanism was done against other ignition delay time data from the literature. All computed results are satisfactorily close to the experimental data.