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Structure of the Soot Growth Region of Laminar Premixed Methane/Oxygen FlamesThe structure of the soot growth region of laminar premixed methane/oxygen flames (fuel-equivalence ratios of 1.60-2.77) was studied both experimentally and computationally. Measurements were carried out in flames stabilized on a flat flame burner operated at standard temperature and pressure, and included velocities by laser velocimetry, soot volume fractions by laser extinction, soot temperatures by multiline emission, gas temperatures (where soot was absent) by corrected fine-wire thermocouples, major gas species concentrations by sampling and gas chromatography, and hydrogen atom concentrations by the Li/LiOH technique in conjunction with atomic absorption to find the proportion of free lithium in the flames. The measured concentrations of major gas species were in reasonably good agreement with predictions based on the detailed mechanisms of Leung and Lindstedt, and Frenklach and coworkers. The measurements also confirmed predictions of both these mechanisms that H-atom concentrations are in local thermodynamic equilibrium throughout the soot growth region even through the concentrations of major gas species are not. Thus, present findings support recent evaluations of the hydrogen-abstraction/carbon-addition (HACA) soot growth mechanism in similar flames, where the approximation that H-atom concentrations were in local thermodynamic equilibrium was adopted, based on predictions using the two mechanisms, due to the absence of direct H-atom concentration measurements.
Document ID
20030016527
Acquisition Source
Glenn Research Center
Document Type
Reprint (Version printed in journal)
Authors
Xu, F.
(Michigan Univ. Ann Arbor, MI United States)
Faeth, G. M.
(Michigan Univ. Ann Arbor, MI United States)
Yuan, Z.-G.
Urban, D. L.
Yuan, Z.-G.
Date Acquired
August 21, 2013
Publication Date
January 1, 2000
Publication Information
Publication: Combustion and Flame
Publisher: Elsevier Science, Inc.
Volume: 121
ISSN: 0010-2180
Subject Category
Inorganic, Organic And Physical Chemistry
Funding Number(s)
CONTRACT_GRANT: NAG3-1878
CONTRACT_GRANT: NAG3-1245
CONTRACT_GRANT: NAG3-2048
Distribution Limits
Public
Copyright
Other

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