Impact of Equivalence Ratio on the Macrostructure of Premixed Swirling CH[subscript 4]/Air and CH[subscript 4]/O[subscript 2]/CO[subscript 2] Flames
Name
Ghoniem_Impact of.pdf
Size
1.81 MB
Format
Adobe PDF
Checksum (MD5)
e37a16df76c9aba08819b368c2f60236
Author(s)
Watanabe, Hirotatsu
Shanbhogue, Santosh J.
Ghoniem, Ahmed F.
Shanbhogue, Santosh
Ghoniem, Ahmed F
Alternative Title
Impact of Equivalence Ratio on the Macrostructure of Premixed Swirling CH4/Air and CH4/O2/CO2 Flames
Date Issued
June 2015
Journal
Proceedings of ASME Turbo Expo 2015: Turbine Technical Conference and Exposition GT2015
Publisher
American Society of Mechanical Engineers (ASME)
Citation
Watanabe, Hirotatsu, Santosh J. Shanbhogue, and Ahmed F. Ghoniem. “Impact of Equivalence Ratio on the Macrostructure of Premixed Swirling CH [subscript 4]/Air and CH[subscript 4]/O[subscript 2]/CO[subscript 2] Flames.” ASME Turbo Expo 2015: Turbine Technical Conference and Exposition, 15-19 June, 2015, Montréal, Canada , ASME, 2015.
Version
Final published version
Abstract
Premixed CH[subscript 4]/O[subscript 2]/CO[subscript 2] flames (oxy-flames) and CH[subscript 4]/air flames (air-flames) were experimentally studied in a swirl-stabilized combustor. For comparing oxy and air flames, the same equivalence ratio and adiabatic flame temperature were used. CO[subscript 2] dilution was adjusted to attain the same adiabatic temperature for the oxy-flame and the corresponding air-flame while keeping the equivalence ratio and Reynolds number (=20,000) the same. For high equivalence ratios, we observed flames stabilized along the inner and outer shear layers of the swirling flow and sudden expansion, respectively, in both flames. However, one notable difference between the two flames appears as the equivalence ratio reaches 0.60. At this point, the outer shear layer flame disappears in the air-flame while it persists in the oxy-flame, despite the lower burning velocity of the oxy-flame. Prior PIV measurements (Ref. 9) showed that the strains along the outer shear layer are higher than along the inner shear layer. Therefore, the extinction strain rates in both flames were calculated using a counter-flow premixed twin flame configuration. Calculations at the equivalence ratio of 0.60 show that the extinction strain rate is higher in the oxy than in the air flame, which help explain why it persists on the outer shear layer with higher strain rate. It is likely that extinction strain rates contribute to the oxy-flame stabilization when air flame extinguish in the outer shear layer. However, the trend reverses at higher equivalence ratio, and the cross point of the extinction strain rate appears at equivalence ratio of 0.64.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1115/GT2015-43224
