Laminar flame speeds, counterflow ignition, and kinetic modeling of the butene isomers

Laminar flame speeds and ignition temperatures of nonpremixed counterflow were measured experimentally for the butene isomers at normal and elevated pressures. Results show that the flame speed increases in the order of isobutene, trans-2-butene, and 1-butene. Furthermore, isobutene has the highest ignition temperature, while those of trans-2-butene and cis-2-butene are quite similar to each other and are slightly higher than that of 1-butene. These results indicate that the reactivities of the butene isomers increase in the order of isobutene, 2-butene, and 1-butene. Furthermore, the critical reaction paths for butene isomer oxidation during ignition were analyzed by sensitivity analysis and a new kinetic model was developed with updated rate coefficients from ab initio calculation and kinetic theories. Simulations with the present kinetic model agree well with the measured laminar flame speeds, counterflow ignition temperatures as well as recent laminar flame speciation and ignition delay times for all butene isomers.