Fuel lewis number effects in unsteady Burke-Schumann hydrogen flames

Marcos Chaos, Ruey Hung Chen*, Eric J. Welle, William Roberts

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Flame response (as determined by temperature and flame thickness) to unsteady hydrodynamics has been measured in acoustically pulsed Burke-Schumann hydrogen flames at two different oscillation frequencies and amplitudes. The effect of fuel Lewis number (LeF) on flame dynamics is isolated by investigating steady and unsteady 40% H2/60% He (LeF > 1) and 40% H2/60% Ar (LeF < 1) flames. For a given flame with LeF < 1, local temperature was found to increase with stretch imparted on the reaction zone by the unsteady flow, whereas the opposite trend was observed for the LeF > 1 flame. Unsteadiness might qualitatively alter the effect of the fuel Lewis number. Notably, for Le F < 1 flames under oscillations of sufficiently high frequency and amplitude, the temperature at the flame tip is higher than that in the shoulder regions, and is different from the temperature field of both steady and low-frequency oscillation flames. This suggests that the effect of unsteady flame stretch may overwhelm that of the flame curvature for sufficiently high unsteadiness.

Original languageEnglish (US)
Pages (from-to)75-88
Number of pages14
JournalCombustion science and technology
Volume177
Issue number1
DOIs
StatePublished - Jan 1 2005

Keywords

  • Curvature
  • Diffusion flame
  • Lewis number
  • Pulsation
  • Stretch
  • Unsteadiness

ASJC Scopus subject areas

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

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