Morphology and self-acceleration of expanding laminar flames with flame-front cellular instabilities

Sheng Yang, Abhishek Saha, Fujia Wu, Chung K. Law

Research output: Contribution to journalArticlepeer-review

47 Scopus citations

Abstract

We report herein experimental observation and mechanistic interpretation of the evolution and self-acceleration of constant-pressure, spherically expanding H2/O2/N2 flames, subjected to hydrodynamic and diffusional-thermal instabilities over a wide range of pressure, equivalence ratio and thermal expansion ratio. Results show the existence of three distinct stages of flame propagation affected by the development of the instability cells, namely smooth expansion, transition, and saturated states of cell development. The onset of the instabilities is primarily controlled by the diffusional-thermal instability, while characteristics of the subsequent transition to and maintenance of the saturated state is controlled by the hydrodynamic instability. The acceleration exponent for the fully developed saturated instability is found to be around 1.2–1.4, which is smaller than 1.5, the suggested value for self-turbulization.

Original languageEnglish (US)
Pages (from-to)112-118
Number of pages7
JournalCombustion and Flame
Volume171
DOIs
StatePublished - Sep 1 2016

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Chemical Engineering(all)
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Physics and Astronomy(all)

Keywords

  • Diffusional-thermal instability
  • Expanding flame
  • Hydrodynamic instability
  • Self-similar propagation

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