Multi-frame visualization for detonation wave diffraction

Y. Nagura, J. Kasahara, Akiko Matsuo

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

When a detonation wave emerges from a tube into unconfined space filled with a gas mixture, detonation wave diffraction occurs due to abrupt changes in the cross-sectional area. In the present study, we focused on the local explosion in reinitiation and propagation of a transverse detonation wave by performing comprehensive and direct observation with high time resolution visualization in a two-dimensional rectangular channel. Using the visualization methods of shadowgraph and multi-frame, short-time, open-shutter photography, we determined where the wall reflection point is generated, and also determined where the bright point is originated by the local explosion, and investigated the effects of the deviation angle and initial pressure of the gas mixture. We found that the reinitiation of detonation had two modes that were determined by the deviation angle of the channel. If the deviation angle was less than or equal to 30(Formula presented.), the local explosion of reinitiation might occur in the vicinity of the channel wall, and if the deviation angle was greater than or equal to 60(Formula presented.), the local explosion might originate on the upper side of the tube exit. With a deviation angle greater than 60(Formula presented.), the position of the wall reflection point depended on the cell width, so the radial distance of the wall reflection point from the apex of the tube exit was about 12 times the cell width. Similarly, the bright point (local explosion point) was located a distance of about 11 times the cell width from the apex of the tube exit, with a circumferential angle of 48(Formula presented.).

Original languageEnglish
Pages (from-to)1-12
Number of pages12
JournalShock Waves
DOIs
Publication statusAccepted/In press - 2016 May 28

Keywords

  • Detonation
  • Detonation diffraction
  • Detonation initiation
  • Multi-frame photograph
  • Schlieren method
  • Shadowgraph method

ASJC Scopus subject areas

  • Mechanical Engineering
  • Physics and Astronomy(all)

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