High-temperature ignition delay times and kinetic study of furan

High-temperature ignition delay times of furan were measured behind the reflected shock waves at the elevated pressures (1.2-10.4 atm) for the mixtures with equivalence ratios of 0.5, 1.0, and 2.0 and furan concentrations of 0.25, 0.5 and 1% diluted in argon. An empirical equation was formulated to correlate the measured ignition delay times with the experimental parameters. The measured ignition delay times at 1.2 atm were compared to numerical predictions using a recently developed furan kinetic mechanism (Mech FR), and the results showed that the model yields reasonable agreement with experiments at an equivalence ratio of 2.0 but significant disagreement at the equivalence ratios of 1.0 and 0.5. A modified kinetic model was built by refining rate constants of selected reactions in Mech FR based on the sensitivity analysis results. The modified mechanism yields remarkably better performance in predicting the ignition delay times as well as the thermal decomposition results. Furthermore, the modified mechanism indicates that the most important fuel consumption path is through the unimolecular initiation reaction: furan = FA (CH ₂CCHCHO), instead of the H abstraction reactions, which were suggested by Mech FR.