Lewis number effects on edge-flame propagation in lifted turbulent flames

Shahram Karami, Mohsen Talei, Evatt R. Hawkes, Hongfeng Yu

Research output: Chapter in Book/Report/Conference proceedingConference PaperResearchpeer-review

Abstract

Three turbulent lifted slot-jet flames of different fuel Lewis numbers are studied using direct numerical simulation (DNS). To reduce the computational cost, a one-step chemistry model is employed with a mixture-fraction dependent activation energy reproducing the dependence of the laminar flame speed on the equivalence ratio which is representative of hydrocarbon fuels. In addition to turbulent flames, axisymmetric laminar jet flames with a same chemistry model to that of turbulent flames are simulated. It is found that the maximum reaction rate decreases as the Lewis number increases in the laminar cases. Analysis of the turbulent cases reveals that the extinction limit is affected by the Lewis number of the fuel. The scalar dissipation rate of the extinction limit increases as the Lewis number decreases. For a given positive curvature, the conditional edge-flame propagation velocity on the curvature increases as the Lewis number decreases. This is similar to the observation in premixed flames and can be explained based on thermo-diffusive effects.
Original languageEnglish
Title of host publicationAustralian Combustion Symposium 2015 Proceedings
EditorsYi Yang, Nigel Smith
Place of PublicationMelbourne Vic Australia
PublisherThe Combustion Institute - Australian and New Zealand Section
Pages300-303
Number of pages4
Publication statusPublished - Dec 2015
Externally publishedYes
EventAustralian Combustion Symposium 2015 - University of Melbourne, Melbourne, Australia
Duration: 7 Dec 20159 Dec 2015

Publication series

NameAustralian Combustion Symposium
ISSN (Print)1839-8170
ISSN (Electronic)1839-8162

Conference

ConferenceAustralian Combustion Symposium 2015
CountryAustralia
CityMelbourne
Period7/12/159/12/15

Keywords

  • Turbulent lifted flames
  • Lewis Number
  • Edge-flames
  • Triple flames

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