Spiral waves in expanding hydrogen-air flames: Experiment and theory

G. Jomaas, J. K. Bechtold, C. K. Law

Research output: Contribution to journalConference article

25 Scopus citations

Abstract

We report herein the first experimental observation of spiral waves over propagating flame surfaces in rich hydrogen-air mixtures at elevated pressures up to 40 atm, conducted in a specially designed, optically accessible, constant-pressure combustion chamber. The observed spiral waves are a manifestation of the large Lewis number instability, exhibiting behaviors such as clockwise/counterclockwise rotation, meandering, and fast radial wave speeds that are similar to patterns often observed in other excitable media, for example the Belousov-Zhabotinsky reaction. In addition, these spiral waves also exhibit features that seem to be characteristic of combustion systems, such as the transition criterion for diffusional-thermal pulsating instability, and their confinement within the hydrodynamic cells that also develop over such high-pressure flames of much reduced flame thicknesses. A diffusional-thermal theory was developed that successfully describes the observed spiral patterns.

Original languageEnglish (US)
Pages (from-to)1039-1046
Number of pages8
JournalProceedings of the Combustion Institute
Volume31 I
Issue number1
DOIs
StatePublished - Jan 1 2007
Event31st International Symposium on Combustion - Heidelberg, Germany
Duration: Aug 5 2006Aug 11 2006

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Mechanical Engineering
  • Physical and Theoretical Chemistry

Keywords

  • Excitable media
  • Hydrogen combustion
  • Pulsating instability
  • Reaction-diffusion spiral waves
  • Target patterns

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