TY - JOUR
T1 - Numerical investigation of the mechanism behind the deflagration to detonation transition in homogeneous and inhomogeneous mixtures of H2-air in an obstructed channel
AU - Shamsaddinsaeid, Mohammadhossein
AU - Khadem, Javad
AU - Emami, Sobhan
PY - 2021/6/15
Y1 - 2021/6/15
N2 - 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.
AB - 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.
KW - Flame acceleration
KW - Deflagration-to-detonation transition
KW - Inhomogeneous mixture
KW - Hydrogen
KW - Obstacle spacing
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85105013151&partnerID=MN8TOARS
UR - https://www.sciencedirect.com/science/article/abs/pii/S0360319921012568
U2 - 10.1016/j.ijhydene.2021.04.006
DO - 10.1016/j.ijhydene.2021.04.006
M3 - Article
SN - 0360-3199
VL - 46
SP - 21657
EP - 21671
JO - International Journal of Hydrogen Energy
JF - International Journal of Hydrogen Energy
IS - 41
ER -