Flame propagation in millimeter-scale tubes for lean ethylene–oxygen mixtures

Ning Du, Wenjun Kong, Wenhu Han, Yiguang Ju

Research output: Contribution to journalArticle

Abstract

Effects of tube diameter and equivalent ratio on flame propagation characteristics of lean ethylene–oxygen mixtures in millimeter-scale cylindrical tubes were experimentally investigated. Five different flame propagation modes—1) steady propagation mode (SPM), 2) jerky flame mode (JFM), 3) oscillating flame mode (OFM), 4) oscillating flame transition to detonation (OFTD), and 5) jerky flame transition to detonation (JFTD)—are observed experimentally with the increase of equivalent ratio. The results show that the oscillation characteristics strongly depend on the tube diameter and mixture composition. The results show that the smaller the diameter of the tube, the more regular and smaller the flame oscillation cycles and amplitude, and the greater the influence of the heat loss on flame propagation. Under the same tube diameter, the ratio of the heat loss to total chemical heat release rate in the five flame modes is Hloss SPM > Hloss JFM > Hloss OFM > Hloss OFTD > Hloss JFTD . The coupling between the wall heat loss, wall friction, and the flame boundary layers contributes significantly to the observed different flame modes and the transition from deflagration to detonation. In addition, the mechanism of oscillating flame propagation is revealed for the first time by numerical simulations.

Original languageEnglish (US)
Pages (from-to)1337-1347
Number of pages11
JournalAIAA journal
Volume58
Issue number3
DOIs
StatePublished - Jan 1 2020

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering

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