Experimental and Kinetic Study on the Ignition Delay Times of 2,5-Dimethylfuran and the Comparison to 2-Methylfuran and Furan

The ignition phenomena of 2,5-dimethylfuran (DMF), 2-methylfuran (MF), and furan are systematically investigated. Ignition delay times are measured over the temperature range of 1150-2010 K and pressures of 1.2, 4, and 16 bar for lean, stoichiometric, and rich DMF/Ar/O-2 mixtures. For comparison, similar measurements for stoichiometric MF/O-2/Ar and furan/O-2/Ar are also conducted. Through a multi-regression analysis, the measured ignition delay times of DMF are fitted empirically in an Arrhenius-like form as a function of experimental parameters. It is observed that, when the fuel concentration, pressure, temperature, and equivalence ratio are kept constant, furan has the longest ignition delay times, while the reactivity of DMF and MF strongly depends upon the temperature. The experimental ignition delay times are compared to model predictions of Somers et al. and Liu et al. Both models could give qualitative agreement with DMF and MF ignition data, while the model of Somers et al. provides better quantitative agreement. Modifications have been made to the model of Somers et al. to agree better with present ignition delay times and other sets of furan data. Further reaction pathway and sensitivity analysis are carried out to understand their combustion kinetics.