Dynamics of an edge-flame in the corner region of two mutually perpendicular streams

Vadim N. Kurdyumov, Moshe Matalon

Research output: Contribution to journalConference articlepeer-review

Abstract

The stabilization and dynamics of an edge-flame in the corner region of two mutually perpendicular streams, one of fuel and the other of oxidizer, is studied within the context of a diffusive-thermal model, with an imposed flow satisfying the Navier-Stokes equations. The formulation allows for non-unity Lewis numbers and finite rate chemis'try with an Arrhenius dependence on temperature. Two flow configurations, corresponding to inlet velocity profiles of uniform speed and of constant strain, have been examined. The results identify the dependence of the flame standoff distance on the flow as well as on the properties of the mixture, including the Damköhler D and Lewis numbers. For high flow rates, or small enough D, sufficient pre-mixing occurs in front of the edge-flame, which consequently takes on a tribrachial structure consisting of two premixed branches, one lean and one rich, with a trailing diffusion flame sheet. For large D, however, there is no enough premixing and the chemical reaction occurs in a small kernel very close to the corner, much like a local thermal explosion; further downstream the reaction occurs along a diffusion flame sheet that extends along the symmetry axis. The present results also predict the onset of spontaneous oscillations when the Lewis numbers are sufficiently large provided the flow rate is sufficiently high, or D reduced below a critical value. Oscillations are first sustained when D is reduced below criticality, but depending on the flow conditions, they are either damped leading to flame re-stabilization, or amplified leading to blow-off.

Original languageEnglish (US)
Pages (from-to)929-938
Number of pages10
JournalProceedings of the Combustion Institute
Volume31 I
Issue number1
DOIs
StatePublished - 2007
Externally publishedYes
Event31st International Symposium on Combustion - Heidelberg, Germany
Duration: Aug 5 2006Aug 11 2006

Keywords

  • Blow-off
  • Diffusion flame
  • Diffusive-thermal
  • Edge-flame
  • Heat loss
  • Instabilities
  • Oscillations
  • Restabilization

ASJC Scopus subject areas

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

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