Laminar flame speeds of H{sub 2}/CO mixtures: Effect of CO{sub 2} dilution, preheat temperature, and pressure

Journal Article · Mon Oct 15 04:00:00 EDT 2007 · Combustion and Flame

DOI:https://doi.org/10.1016/J.COMBUSTFLAME.2007.05.003· OSTI ID:20961961

Natarajan, J; Lieuwen, T; Seitzman, J ^[1]

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1. School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0150 (United States)

Laminar flame speeds of lean H{sub 2}/CO/CO{sub 2} (syngas) fuel mixtures have been measured over a range of fuel compositions (5-95% for H{sub 2} and CO and up to 40% for CO{sub 2} by volume), reactant preheat temperatures (up to 700 K), and pressures (1-5 atm). Two measurement approaches were employed: one using flame area images of a conical Bunsen flame and the other based on velocity profile measurements in a one-dimensional stagnation flame. The Bunsen flame approach, based on imaging measurements of the reaction zone area, is shown to be quite accurate for a wide range of H{sub 2}/CO compositions. These data were compared to numerical flame speed predictions based on two established chemical mechanisms: GRI Mech 3.0 and the Davis H{sub 2}/CO mechanism with detailed transport properties. For room temperature reactants, the Davis mechanism predicts the measured flame speeds for the H{sub 2}/CO mixtures with and without CO{sub 2} dilution more accurately than the GRI mechanism, especially for high H{sub 2} content compositions. The stagnation flame measurements for medium levels of H{sub 2} at both 1 and 5 atm, however, show lower than predicted strain sensitivities, by almost a factor of two at lean conditions ({phi}=0.6-0.8). At preheat temperatures comparable to those found in gas turbine combustors, the accuracy of the flame speed predictions worsens. For example in fuels with low levels of H{sub 2}, both models underpredict the measurements. In contrast, for medium H{sub 2} content fuels, both measurement techniques show that the models tend to overpredict flame speed, with the discrepancy increasing as {phi} decreases and temperature increases. In general, the Davis mechanism predictions are in good agreement with the measurements for medium and high H{sub 2} fuels for preheat temperatures up to 500 K but overpredict the measurements at higher temperatures. (author)

• OSTI ID: 20961961
• Journal Information: Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 1-2 Vol. 151; ISSN CBFMAO; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ACCURACY
CARBON DIOXIDE
CARBON MONOXIDE
CHEMICAL COMPOSITION
COMBUSTORS
DILUTION
FORECASTING
GAS TURBINES
HYDROGEN
IMAGES
LAMINAR FLAMES
MIXTURES
ONE-DIMENSIONAL CALCULATIONS
PRESSURE DEPENDENCE
PRESSURE RANGE KILO PA
SENSITIVITY
STRAINS
SYNTHESIS GAS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0400-1000 K
VELOCITY