title: Suppression of methane/air explosion by ultrafine water mist containing sodium chloride additive.
abstract: The suppression effect of ultrafine mists on methane/air explosions with methane concentrations of 6.5%, 8%, 9.5%, 11%, and 13.5% were experimentally studied in a closed visual vessel. Ultrafine water/NaCl solution mist as well as pure water mist was adopted and the droplet sizes of mists were measured by phase doppler particle analyzer (PDPA). A high speed camera was used to record the flame evolution processes. In contrast to pure water mist, the flame propagation speed, the maximum explosion overpressure (ΔP(max)), and the maximum pressure rising rate ((dP/dt)max) decreased significantly, with the "tulip" flame disappearing and the flame getting brighter. The results show that the suppressing effect on methane explosion by ultrafine water/NaCl solution mist is influenced by the mist amount and methane concentration. With the increase of the mist amount, the pressure, and the flame speed both descended significantly. And when the mist amount reached 74.08 g/m(3) and 37.04 g/m(3), the flames of 6.5% and 13.5% methane explosions can be absolutely suppressed, respectively. All of results indicate that addition of NaCl can improve the suppression effect of ultrafine pure water mist on the methane explosions, and the suppression effect is considered due to the combination effect of physical and chemical inhibitions.
authors.affiliation: School of Chemical Machinery, Dalian University of Technology, No.2 Linggong Road, Ganjingzi District,Dalian, Liaoning 116024, PR China.
authors.forename: Xingyan
authors.initials: X
authors.lastname: Cao
authors.affiliation: School of Chemical Machinery, Dalian University of Technology, No.2 Linggong Road, Ganjingzi District,Dalian, Liaoning 116024, PR China.
authors.forename: Jingjie
authors.initials: J
authors.lastname: Ren
authors.affiliation: School of Chemical Machinery, Dalian University of Technology, No.2 Linggong Road, Ganjingzi District,Dalian, Liaoning 116024, PR China.
authors.forename: Yihui
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: School of Chemical Machinery, Dalian University of Technology, No.2 Linggong Road, Ganjingzi District,Dalian, Liaoning 116024, PR China.
authors.forename: Qiuju
authors.initials: Q
authors.lastname: Wang
authors.affiliation: School of Chemical Machinery, Dalian University of Technology, No.2 Linggong Road, Ganjingzi District,Dalian, Liaoning 116024, PR China.
authors.forename: Xuliang
authors.initials: X
authors.lastname: Gao
authors.affiliation: School of Chemical Machinery, Dalian University of Technology, No.2 Linggong Road, Ganjingzi District,Dalian, Liaoning 116024, PR China. Electronic address: bimsh@dlut.edu.cn.
authors.forename: Mingshu
authors.initials: M
authors.lastname: Bi
mesh_terms: D000388:Air; D005107:Explosions / Q000517:prevention & control*; D008697:Methane / Q000737:chemistry*; D011312:Pressure; D012965:Sodium Chloride / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D012965:Sodium Chloride; D008697:Methane
keywords: Explosion suppression; Flame speed; Methane/air explosion; Sodium chloride; Ultrafine water mist