Effect of Molecular Structure on Laminar Flame Speeds of Three C5 Alkenes

Abstract

ABSTRACTThe laminar flame speeds of 1-pentene and 2-methyl-2-butene are measured in our previous studies. In order to study the effect of molecular structure on the combustion characteristics of C5 alkenes, the laminar flame speeds of 2-pentene/air mixtures were measured in a constant volume combustion bomb in the different conditions (T0 = 450 K, p = 0.1/0.3 MPa, and φ = 0.6–1.6). Experimental results for the three fuels show that 1-pentene has the largest laminar flame speeds, and 2-methyl-2-butene has the lowest one. Further, a high-temperature chemical mechanism for C5 alkenes was developed to analyze the differences in laminar flame speeds between the three fuels and to explore the effects of molecular structure on the combustion characteristics of the three C5 alkenes. The chemical mechanism was verified by the experimental results of laminar flame speeds and can well predict the combustion characteristics of these three C5 alkenes over a wide range of conditions. The effects of molecular structure on laminar flame speed were analyzed by the chemical kinetic model from three aspects: bond dissociation energies, reaction pathways, and sensitivity analyses. Results show that the chemical kinetic characteristics of linear 1-pentene and 2-pentene are similar to each other, while the chemical kinetic characteristics of branched 2-methyl-2-butene differ greatly from them.