Formation and characteristics of composite reaction - Shock clusters in narrow channels

Hao Wei Ssu, Ming Hsun Wu

Research output: Contribution to journalConference articlepeer-review

10 Citations (Scopus)


High-speed schlieren visualizations show that a composite reaction-shock cluster structure is formed in the last flame acceleration stage prior to detonation transition for ethylene/oxygen mixture in a narrow channel. The composite structure is bounded by a normal shock at the leading edge of the structure, and series of parallel oblique shocks interweave with reaction front on the other end in the cluster. Propagating velocity of the reaction front at the inception of the cluster is ∼45-50% of Chapman-Jouguet detonation velocity of the mixture. Reaction front accelerates rapidly after the formation of the reaction-shock cluster, and run into detonation in tens of microseconds except for very lean mixtures. The angle between the parallel oblique shocks in the cluster and the side wall, defined as ω-angle, is found to be constant for a specific mixture as the reaction wave propagates. Dependence of ω-angle on mixture equivalence ratio and channel size are investigated in the study. Analysis shows that DDT distance is linearly proportional to ω-angle, and an empirical correlation is derived.

Original languageEnglish
Pages (from-to)3473-3480
Number of pages8
JournalProceedings of the Combustion Institute
Issue number3
Publication statusPublished - 2021
Event38th International Symposium on Combustion, 2021 - Adelaide, Australia
Duration: 2021 Jan 242021 Jan 29

All Science Journal Classification (ASJC) codes

  • General Chemical Engineering
  • Mechanical Engineering
  • Physical and Theoretical Chemistry


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