Measurements of Laminar Burning Velocities and Markstein Lengths of 2,5-Dimethylfuran−Air−Diluent Premixed Flames

Laminar burning velocities and Markstein lengths of 2,5-dimethylfuran (DMF)−air−N2/CO2 premixed mixtures at the atmospheric pressure and initial temperature of 393 K over three different dilution ratios were obtained by using the outwardly propagating spherical flame and high-speed schlieren photograph system. Addition of diluent was used to simulate the effects of exhaust gas recirculation on the flame propagation. The results show that both unstretched flame propagation speed and laminar burning velocity decrease with the increase of dilution ratio. Markstein length is increased with the increase of dilution ratio, indicating that addition of diluent will improve the stability of the flame. The dilution effects of CO2 as diluent on the flame propagation and the flame stability are stronger than those of N2 as diluent. For a specific equivalence ratio, the laminar burning velocity shows a linear decreasing trend with the increase of dilution ratio. The ratio of the laminar burning velocities with and without diluent gas (the normalized laminar burning velocity) demonstrates good linear trend versus the dilution ratio, and a linear formula is developed to express this relationship based on experimental data.