Shock-tube experiments and kinetic modeling of 2-methylfuran ignition at elevated pressure

Ignition delays of 2-methylfuran were measured behind reflected shock waves over a wide range of experimental conditions: equivalence ratios from 0.25 to 2.0, average pressures from 1.25 to 10.65 bar, temperatures from 1120 to 1700 K, and oxygen concentrations up to 20%. Results show that the ignition delay decreases with increasing the pressure and decreasing the dilution ratio. For a given dilution ratio, there exists a crossover in the ignition delay time dependence upon the equivalence ratio and the crossing point shifts to the higher temperature at a higher pressure. The measured ignition delays of 2-methylfuran show good agreement with the previous data at atmospheric pressure. The 2-methylfuran model NUI-MF2 well predicts the ignition delays of 2-methylfuran at 1.25 bar but gives the underprediction when pressures are elevated to 4.25 and 10.65 bar. Sensitivity analysis identifies the importance of the reactions involving the n-butadienyl radical (C₄H ₅-n) in the ignition process of 2-methylfuran. Better prediction on ignition delay times is achieved by perturbing the rate constants of β-scission reactions for the C₄H₅-n radical, and these perturbations do not affect the primary fuel consumption flux based on the reaction pathway analysis.