Experimental Study on Laminar Burning Characteristics of Premixed 2,5-Dimethylfuran/Air Mixtures at Elevated...

Experimental studies of laminar burning velocity and flame instabilities of 2,5-dimethylfuran (DMF) were conducted at different equivalence ratios (from 0.9 to 1.3), initial pressures (from 0.1 to 0.8 MPa), and initial temperatures (from 393 to 493 K) by the method of the schlieren and high-speed photography system in the constant-volume combustion bomb. The results showed that the laminar burning velocity of the DMF/air flame decreased with increasing initial pressure and increased with increasing initial temperature. The maximum laminar burning velocity occurred at φ = 1.1, regardless of the initial pressure and temperature conditions. The power law fitting of baric coefficients, thermal coefficients, and laminar burning velocity was obtained, and the laminar burning velocity of DMF/air flame can be predicted well in the study range. The diffusive-thermal instability of the DMF/air flame was more pronounced during rich combustion. Increasing the initial pressure increased both the diffusive-thermal instability and the hydrodynamic instability of the flame, while increasing the initial temperature increased the diffusive-thermal instability of the flame, which was mainly responsible for flame propagation. In addition, the Markstein length, density ratio, flame thickness, critical radius, acceleration index, and classification excess of the DMF/air flame were investigated. The results of this paper provide a theoretical support for the application of DMF in engineering.