Transition to detonation of an expanding flame ring in a sub-millimeter gap

Ming Hsun Wu, Wei Chun Kuo

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


Deflagration-to-detonation transition of a flame ring circularly expanding in a 260μm gap filled with stoichiometric ethylene/oxygen mixtures initially at atmospheric pressure and temperature has been experimentally visualized. The results show that DDT can occur under the influence of wall confinement even for an expanding flame. DDT could be observed at a distance as short as ~70. mm from the ignition spot, which corresponds to ~130μs after the ignition spark voltage breakdown. Velocity overshoot of reaction front velocity exceeding Chapman-Jouguet velocity was characterized. Cell structures were observed on the reaction fronts after DDT occurred. The visualizations also showed that smooth circular flame developed right after ignition quickly evolved into wrinkled flame as the flame ring propagated outwards. Flame propagating velocity was accelerated from ~600. m/s to ~1000. m/s during the wrinkled flame stage. A series of local explosion on the flame ring was observed during the DDT process, and resulted in an abrupt surge on reaction front propagation velocity.

Original languageEnglish
Pages (from-to)1366-1368
Number of pages3
JournalCombustion and Flame
Issue number3
Publication statusPublished - 2012 Mar

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • General Chemical Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology
  • General Physics and Astronomy


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