Experimental and kinetic study on the laminar premixed cyclopentene/air flames

• Published in: Fuel (Guildford) Vol. 278; p. 118382
• Main Authors: Zhong, Bei-jing, Zeng, Zhao-mei
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15.10.2020; Elsevier BV
• Subjects: Adiabatic; Alkenes; C5 alkenes; Chain branching; Combustion; Combustion temperature; Cyclopentene; Flame instabilities; Flame speed; Flame stability; Flames; Free radicals; Instability; Kinetic modeling; Laminar flame speeds; Molecular chains; Radicals; Stability analysis; Flame instabilities; Laminar flame speeds; Kinetic modeling; C5 alkenes; Cyclopentene
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2020.118382

•The experimental laminar flame speeds of cyclopentene were measured.•A unified chemical kinetic model of C5 alkenes was developed.•Combustion and kinetic characteristics of three C5 alkenes were compared.•The flame speeds of CYC5H8 and BC5H10 are similar, but lower than that of C5H10-1. Laminar flame speeds of cyclopentene at different conditions (T = 450 K, p = 0.1 and 0.3 MPa and φ = 0.6–1.6) were measured in a constant volume combustion bomb. To better understand the effect of cyclic structure on combustion characteristics, laminar flame speeds of cyclopentene were compared with the other two C5 alkenes (1-pentene and 2-methyl-2-butene, which are straight-chain molecule and branched-chain molecule, respectively). Results show that the laminar flame speed of cyclopentene is close to that of 2-methyl-2-butene, but lower than that of 1-pentene. Both hydrodynamic instability and thermal-diffusive instability were used to analyze the flame instability. Results show that 1-pentene flame suffers the strongest hydrodynamic instability, while cyclopentene flame suffers the strongest thermal-diffusive instability. A unified chemical kinetic model of C5 alkenes was developed, which can well predict the ignition and combustion characteristics of three C5 alkenes (1-pentene, 2-methyl-2-butene and cyclopentene) in different conditions. In addition, chemical kinetic analysis using the updated model shows that cyclopentene has a higher adiabatic combustion temperature than 1-pentene and 2-methyl-2-butene, which can increase the reactivity. However, cyclopentene has a strong ability to consume H and OH radicals and generate stabilized radicals, which in turn reduces the global reaction rate, thereby reducing the laminar flame speeds.