Time-series analysis and measurements of intermediate-species concentration spectra in turbulent non-premixed flames

M. W. Renfro, Y. R. Sivathanu, J. P. Gore, G. B. King, N. M. Laurendeau

Research output: Contribution to journalConference articlepeer-review

9 Scopus citations

Abstract

The ability to make frequency-resolved measurements of minor-species concentrations in turbulent flames has recently been demonstrated by picosecond time-resolved laser-induced fluorescence (PITLIF). However, few previous studies have focused on the power spectral density (PSD) of minor species in reacting flows. What little information is available suggests that strong interactions between velocity fluctuations and scalar distributions complicate the PSD, making interpretation of flame data difficult. In this work, time-series analysis, previously applied in flame-radiation studies, is extended to the study of temporal fluctuations in minor-species concentrations. In particular, an assumed PSD model for mixture fraction (Z) is used to simulate its time series. State relationships for narrowly distributed minor species as a function of mixture fraction are applied to develop concentration time series. Extension of this laminar-flamelet approach to minor species requires additional consideration of the effect of flame strain rate on the width of a minor-species profile in Z space as well as its peak concentration. The resulting minor-species concentration PSDs are computed and studied as a function of profile width (in Z) and fluctuation intensity (ZRMS). These simulations compare favorably to previously reported CH and OH PSDs in a low-Reynolds-number, methane diffusion flame. Similarly, new PITLIF measurements of OH time series in a hydrogen diffusion flame at several Reynolds numbers also demonstrate favorable comparisons to the PSD simulations.

Original languageEnglish
Pages (from-to)1015-1022
Number of pages8
JournalSymposium (International) on Combustion
Volume27
Issue number1
DOIs
StatePublished - 1998
Event27th International Symposium on Combustion - Boulder, CO, United States
Duration: Aug 2 1998Aug 7 1998

Bibliographical note

Funding Information:
The experimental portion of this work is supported by the Air Force Office of Scientific Research, with Dr. Julian Tishkoff as technical monitor. We are grateful to S. D. Pack for helping with the hydroxyl measurements and to R. V. Ravikrishna for supplying the OPPDIF output files used to create the state relationships.

ASJC Scopus subject areas

  • Chemical Engineering (all)
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Mechanical Engineering
  • Physical and Theoretical Chemistry
  • Fluid Flow and Transfer Processes

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