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Soot Surface Growth in Laminar Hydrocarbon/Air Diffusion FlamesThe structure and soot surface growth properties of round laminar jet diffusion flames were studied experimentally. Measurements were made along the axes of ethylene-, propylene-propane- and acetylene-benzene-fueled flames burning in coflowing air at atmospheric pressure with the reactants at normal temperature. The measurements included soot structure, soot concentrations, soot temperatures, major gas species concentrations, some radial species (H, OH and O) concentrations, and gas velocities. These measurements yielded the local flame properties that are thought to affect soot surface growth as well as local soot surface growth rates. When present results were combined with similar earlier observations of acetylene-fueled laminar jet diffusion flames, the results suggested that soot surface growth involved decomposition of the original fuel to form acetylene and H, which were the main reactants for soot surface growth, and that the main effect of the parent fuel on soot surface growth involved its yield of acetylene and H for present test conditions. Thus, as the distance increased along the axes of the flames, soot formation (which was dominated by soot surface growth) began near the cool core of the flow once acetylene and H appeared together and ended near the flame sheet when acetylene disappeared. Species mainly responsible for soot oxidation - OH and O2 were present throughout the soot formation region so that soot surface growth and oxidation proceeded at the same time. Present measurements of soot surface growth rates (corrected for soot surface oxidation) in laminar jet diffusion flames were consistent with earlier measurements of soot surface growth rates in laminar premixed flames and exhibited good agreement with existing Hydrogen-Abstraction/Carbon-Addition (HACA) soot surface growth mechanisms in the literature with steric factors in these mechanisms having values on the order of unity, as anticipated.
Document ID
20020087739
Acquisition Source
Glenn Research Center
Document Type
Preprint (Draft being sent to journal)
Authors
El-Leathy, A. M. (Michigan Univ. Ann Arbor, MI United States)
Xu, F. (Michigan Univ. Ann Arbor, MI United States)
Kim, C. H. (Michigan Univ. Ann Arbor, MI United States)
Faeth, G. M. (Michigan Univ. Ann Arbor, MI United States)
Urban, D. L.
Yuan, Z.-G.
Date Acquired
September 7, 2013
Publication Date
December 15, 2001
Publication Information
Publication: Soot Formation in Freely-Propagating Laminar Premixed Flames
Subject Category
Inorganic, Organic And Physical Chemistry
Funding Number(s)
CONTRACT_GRANT: NAG3-1245
CONTRACT_GRANT: NAG3-2048
CONTRACT_GRANT: NAG3-1878
Distribution Limits
Public
Copyright
Public Use Permitted.

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