title: High methane natural gas/air explosion characteristics in confined vessel.
abstract: The explosion characteristics of high methane fraction natural gas were investigated in a constant volume combustion vessel at different initial conditions. Results show that with the increase of initial pressure, the peak explosion pressure, the maximum rate of pressure rise increase due to a higher amount (mass) of flammable mixture, which delivers an increased amount of heat. The increased total flame duration and flame development time result as a consequence of the higher amount of flammable mixture. With the increase of the initial temperature, the peak explosion pressures decrease, but the pressure increase during combustion is accelerated, which indicates a faster flame speed and heat release rate. The maximum value of the explosion pressure, the maximum rate of pressure rise, the minimum total combustion duration and the minimum flame development time is observed when the equivalence ratio of the mixture is 1.1. Additionally, for higher methane fraction natural gas, the explosion pressure and the maximum rate of pressure rise are slightly decreased, while the combustion duration is postponed. The combustion phasing is empirically correlated with the experimental parameters with good fitting performance. Furthermore, the addition of dilute gas significantly reduces the explosion pressure, the maximum rate of pressure rise and postpones the flame development and this flame retarding effect of carbon dioxide is stronger than that of nitrogen.
authors.affiliation: State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, People's Republic of China. Electronic address: chenglongtang@mail.xjtu.edu.cn.
authors.forename: Chenglong
authors.initials: C
authors.lastname: Tang
authors.affiliation: State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, People's Republic of China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, People's Republic of China.
authors.forename: Zhanbo
authors.initials: Z
authors.lastname: Si
authors.affiliation: State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, People's Republic of China.
authors.forename: Zuohua
authors.initials: Z
authors.lastname: Huang
authors.affiliation: Beijing Green Energy Natural Gas Application Hi-Tech Research Institute, People's Republic of China.
authors.forename: Kongming
authors.initials: K
authors.lastname: Zhang
authors.affiliation: Beijing Green Energy Natural Gas Application Hi-Tech Research Institute, People's Republic of China.
authors.forename: Zebing
authors.initials: Z
authors.lastname: Jin
mesh_terms: D000388:Air; D002245:Carbon Dioxide; D005107:Explosions; D006358:Hot Temperature; D008697:Methane / Q000737:chemistry*; D059206:Natural Gas; D009584:Nitrogen; D011312:Pressure
chemical_list: D059206:Natural Gas; D002245:Carbon Dioxide; D009584:Nitrogen; D008697:Methane
keywords: Combustion phasing; Dilution; Explosion characteristics; High methane concentration natural gas