The large-activation-energy analysis of extinction of counterflow diffusion flames with non-unity Lewis numbers of the fuel Articles uri icon

publication date

  • January 2017

start page

  • 91

end page

  • 106

volume

  • 175

international standard serial number (ISSN)

  • 0010-2180

electronic international standard serial number (EISSN)

  • 1556-2921

abstract

  • Large-activation-energy asymptotic techniques are used to describe the effects of non-unity Lewis numbers of the fuel on strain-induced extinction of axisymmetric counterflow diffusion flames. The present work extends and clarifies previous investigations by accounting also for variable density and variable transport properties of the gas. In our asymptotic analysis the flame structure near extinction is, at leading order, given by the Burke-Schumann limit of infinitely fast reaction; i.e. two outer regions of equilibrium flow, with the fuel and the oxygen separated by an infinitesimally thin reaction layer where they arrive by diffusion in stoichiometric proportions.

keywords

  • diffusion-controlled combustion; activation-energy asymptotics; non-unity lewis number; diffusion-flame extinction; premixed-flame extinction; asymptotic structure; combustion; chemistry