Mechanism insight of shielded methane non-premixed jet flame extinction with water mist: OH-PLIF visualization and quantitative analysis of critical fire extinguishing. (September 2022)

• Record Type: Journal Article
• Authors: Liu, Yangpeng; Wang, Xishi; Tang, Qi; Li, Guochun; Pan, Chuanyu; Liu, Tong; Ni, Xiaomin; Wu, Yingchun
• Is Part Of: Fire safety journal. Volume 132(2022)
• Publication Date: 2022-09
• Subjects: Flame extinction -- Water mist -- Natural gas leakage -- Shielded jet flame -- Obstruction effect; Fire prevention -- Periodicals; Incendies -- Prévention -- Recherche -- Périodiques; Fire prevention -- Research; Periodicals; 628.92205
• DOI: 10.1016/j.firesaf.2022.103642
• Languages: English
• ISSNs: 0379-7112

Abstract

Abstract: Natural gas leaks from pipeline systems or storage sites may highly lead to a fire safety incident as well as a potential major hazard in industries or residential. The leaked jet flame commonly sheltered by an obstacle is more difficult to be extinguished as the result of a reduction in effective extinguishing agent flux and potential re-ignition. Especially in cases where the flame is heavily obscured by obstacles, the interaction of the extinguishing agent and flame can be very different from the unobstructed situation. This study aims to determine the critical characteristics of a water mist to extinguish a shielded non-premixed jet flame with the flame structure visualization of hydroxide planar laser-induced fluorescence (OH-PLIF) and quantitative parametric analysis. The effect of obstacles on water mist and a jet flame is firstly quantitatively evaluated by flame obscuration ratio k f and maximum effective mist ratio k in critical fire-extinguishing cases. Flame dynamical behavior from the base of the flame upwards to extinction is found when the flame Froude number Fr f > 0.74 and k f > 0.75. Finally, the preferred water mist nozzles with larger spray angles might have more effective fire extinguishment ability typically under the cases of k < 0.5 and k f > 1.0. This study would be valuable for the optimum design of water mist systems in natural gas leakage incidents under shielded conditions.