Flame Propagation Characteristic of Cyclohexene/Air Mixtures

Cycloalkenes containing both cyclic and unsaturated structures are promising components for high-speed vehicles. In this paper, the flame propagation characteristics of cyclohexene/air mixtures were investigated in a constant-volume vessel. Kinetic analysis via a detailed mechanism was conducted to further reveal the oxidation mechanism of cyclohexene. Experimental results showed that the flame front got rough with the increase of equivalence ratio and pressure. The increases in equivalence ratio and pressure enhanced the mass diffusion and increased the thickness of the flame front, respectively, thus decreasing the Markstein length and increasing the instability of the flame front. Laminar flame speeds of cyclohexene/air decreased with increasing pressure and increased and then decreased with the increase of equivalence ratio. Kinetic analyses on the sensitivity implied that the flame propagation speeds of cyclohexene were dominated by the reactions of C0 - C2 species. Analyses of the reaction pathways showed that the cyclohexene was mainly decomposed by bond-breaking reactions to rapidly form small molecules. While few contents of cyclohexene turned to benzene via H-abstraction reactions.