LES – DFSD modelling of vented hydrogen explosions in a small-scale combustion chamber.

Mohamed Elshimy, Salah Ibrahim, W. Malalasekera

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)
28 Downloads (Pure)

Abstract

Accidental explosions are a plausible danger to the chemical process industries. In the event of a gas explosion, any obstacles placed within the path of the flame generate turbulence, which accelerates the transient flame and raises explosion overpressure, posing a safety hazard. This paper presents numerical studies using an in-house computational fluid dynamics (CFD) model for lean premixed hydrogen/air flame propagations with an equivalence ratio of 0.7. A laboratory-scale combustion chamber is used with repeated solid obstacles. The transient compressible large eddy simulation (LES) modelling technique combined with a dynamic flame surface density (DFSD) combustion model is used to carry out the numerical simulations in three-dimensional space. The study presented uses eight different baffle configurations with two solid obstructions, which have area blockage ratios of 0.24 and 0.5. The flame speed, maximum rate of pressure-rise as well as peak overpressure magnitude and timing are presented and discussed. Numerical results are validated against available published experimental data. It is concluded that, increasing the solid obstacle area blockage ratio and the number of consecutive baffles results in a raised maximum rate of pressure rise, higher peak explosion overpressure and faster flame propagation. Future model development would require more experimental data, probably in a more congested configuration.
Original languageEnglish
Article number104580
JournalJournal of Loss Prevention in the Process Industries
Volume72
Early online date16 Jun 2021
DOIs
Publication statusPublished - Sept 2021
Externally publishedYes

Keywords

  • Computational fluid dynamics
  • Large eddy simulation
  • Hydrogen combustion
  • Dynamic flame surface density
  • Area blockage ratio
  • Process industries

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