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Combustion in a turbulent mixing layer formed at a rearward-facing stepA premixed propane/air flame was stabilized in a turbulent mixing layer formed at a rearward-facing step. The mean and rms averages of the turbulent velocity flowfield were determined by laser velocimetry for both reacting (phi = 0.57) and nonreacting flows (Re = 15,000-37,000 based on step height). The reacting-flow was visualized by high-speed schlieren photography. Large-scale structures dominate the reacting mixing layer. The growth of the large-scale structures was tied to the propagation of the flame. The linear growth rate of the reacting mixing layer defined by the mean velocity profiles was unchanged by combustion but the virtual origin moves downstream. The reacting mixing layer boundaries based on the mean velocity profiles were shifted toward the recirculation zone and reattachment lengths were shortened by 30 percent. The edge of the flame controlled by the large-scale structure development propagated faster into the incoming reactants than the boundary of the mixing layer given by the mean velocity flowfield. Thus, the region of high velocity gradient did not coincide with the region of high reaction and heat transfer.
Document ID
19840027353
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Pitz, R. W.
(California Univ. Berkeley, CA, United States)
Daily, J. W.
(California, University Berkeley, CA, United States)
Date Acquired
August 12, 2013
Publication Date
November 1, 1983
Publication Information
Publication: AIAA Journal
Volume: 21
ISSN: 0001-1452
Subject Category
Inorganic And Physical Chemistry
Accession Number
84A10140
Funding Number(s)
CONTRACT_GRANT: NSG-3227
CONTRACT_GRANT: NSF-ENG-77-02019
Distribution Limits
Public
Copyright
Other

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