Hydroxyl time series and recirculation in turbulent nonpremixed swirling flames

Walter A. Guttenfelder, Michael W. Renfro, Normand M. Laurendeau, Jun Ji, Galen B. King, Jay P. Gore

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Time-series measurements of OH, as related to accompanying flow structures, are reported using picosecond time-resolved laser-induced fluorescence (PITLIF) and particle-imaging velocimetry (PIV) for turbulent, swirling, nonpremixed methane-air flames. The [OH] data portray a primary reaction zone surrounding the internal recirculation zone, with residual OH in the recirculation zone approaching chemical equilibrium. Modeling of the OH electronic quenching environment, when compared to fluorescence lifetime measurements, offers additional evidence that the reaction zone burns as a partially premixed flame. A time-series analysis affirms the presence of thin flamelet-like regions based on the relation between swirl-induced turbulence and fluctuations of [OH] in the reaction and recirculation zones. The OH integral time-scales are found to correspond qualitatively to local mean velocities. Furthermore, quantitative dependencies can be established with respect to axial position, Reynolds number, and global equivalence ratio. Given these relationships, the OH time-scales, and thus the primary reaction zone, appear to be dominated by convection-driven fluctuations. Surprisingly, the OH time-scales for these nominally swirling flames demonstrate significant similarities to previous PITLIF results in nonpremixed jet flames.

Original languageEnglish
Pages (from-to)11-21
Number of pages11
JournalCombustion and Flame
Issue number1-2
StatePublished - Oct 2006

Bibliographical note

Funding Information:
This work was supported by the Air Force Office of Scientific Research, with Dr. Julian Tishkoff as technical monitor.


  • Hydroxyl
  • Integral time-scale
  • Partial premixing
  • Swirling flames

ASJC Scopus subject areas

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


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