Numerical investigation of the mechanism behind the deflagration to detonation transition in homogeneous and inhomogeneous mixtures of H2-air in an obstructed channel

Mohammadhossein Shamsaddinsaeid, Javad Khadem, Sobhan Emami

Research output: Contribution to journalArticlepeer-review

48 Citations (Scopus)

Abstract

The accidental release of hydrogen into enclosures can result in a flammable mixture with concentration gradients and possible deflagration-to-detonation transition (DDT). This numerical study aims to investigate the effect of obstacle spacing and mixture concentration on the DDT in a homogeneous and inhomogeneous hydrogen-air mixture. The paper focuses on the mechanisms behind the DDT in two mixtures with an average hydrogen concentration of 15% and 30%. Unlike the near-stoichiometric mixture, in the lean mixture, DDT only occurs in the inhomogeneous mixture. Depending on obstacle spacing, three different regimes of DDT were observed in the near-stoichiometric inhomogeneous mixture: i) Detonation was ignited when a strong Mach stem formed and propagated between the obstacles; ii) two explosion centers appeared when incident shock and Mach stem reflected from upper and lower obstacles, respectively; iii) Mach stem did not form but DDT occurred behind the flame front at the top of the obstacle.
Original languageEnglish
Pages (from-to)21657-21671
Number of pages15
JournalInternational Journal of Hydrogen Energy
Volume46
Issue number41
Early online date28 Apr 2021
DOIs
Publication statusPublished (in print/issue) - 15 Jun 2021

Keywords

  • Flame acceleration
  • Deflagration-to-detonation transition
  • Inhomogeneous mixture
  • Hydrogen
  • Obstacle spacing

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