Damage-mutation mode of premixed methane-air explosions in a small-L/D vented vessel

Zehua Wang, Hua Lv*, Dunyu Liu, Tonghao Liu, Zhongqi Wang, Xiaobin Li, Ming Liu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Limited experimental data has led to significant gaps in understanding gas-explosion damage modes in small L/D vessels or constructions. To address this, we developed a novel two-dimensional gas explosion system. In a typical L-shaped vessel, we investigated 10 vol% methane-air explosions under varying vent-ignition conditions and low failure pressures. Influenced by the L-shaped space and vent-ignition relationship, combustion and pressure exhibit strong coupling and mutual reinforcement. Two newly identified flame mutation modes enhance the burning damage of gas explosions. Flame return driven by a pressure gradient, which depends on the volume of unburnt premixed gas, intensifies local combustion and amplifies overpressure, particularly at short vent-ignition distances. Flame collision between two flame fronts, under conditions of abundant unburnt premixed gas and short vent-ignition distances, generates intense turbulence and produces violent combustion. The long vent-ignition distance and L-shaped space mitigate the Helmholtz oscillation while amplifying the overpressure peak P3. The violent combustion caused by the flame collision dramatically increases P4. These atypical peaks, P3 and P4, further exacerbate the overpressure damage. These findings demonstrate that under specific vent-ignition conditions, flame mutation modes can increase the overpressure peak by up to 141 %, underscoring their crucial role in the investigation and prevention of gas explosion incidents.

Original languageEnglish
Article number105658
JournalJournal of Loss Prevention in the Process Industries
Volume96
DOIs
Publication statusPublished - Aug 2025
Externally publishedYes

Keywords

  • Flame collision
  • Flame return
  • Overpressure peak
  • Premixed gas explosion

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