Effects of CO addition on the characteristics of laminar premixed CH{sub 4}/air opposed-jet flames

Journal Article · Sun Feb 15 04:00:00 EST 2009 · Combustion and Flame

DOI:https://doi.org/10.1016/J.COMBUSTFLAME.2008.10.028· OSTI ID:21137921

Wu, C -Y ^[1]; Chao, Y -C; Chen, C -P; Ho, C -T ^[2]; Cheng, T S ^[3]

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1. Advanced Engine Research Center, Kao Yuan University, Kaohsiung County, 821 (China)
2. Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan, 701 (China)
3. Department of Mechanical Engineering, Chung Hua University, Hsinchu, 300 (China)

The effects of CO addition on the characteristics of premixed CH{sub 4}/air opposed-jet flames are investigated experimentally and numerically. Experimental measurements and numerical simulations of the flame front position, temperature, and velocity are performed in stoichiometric CH{sub 4}/CO/air opposed-jet flames with various CO contents in the fuel. Thermocouple is used for the determination of flame temperature, velocity measurement is made using particle image velocimetry (PIV), and the flame front position is measured by direct photograph as well as with laser-induced predissociative fluorescence (LIPF) of OH imaging techniques. The laminar burning velocity is calculated using the PREMIX code of Chemkin collection 3.5. The flame structures of the premixed stoichiometric CH{sub 4}/CO/air opposed-jet flames are simulated using the OPPDIF package with GRI-Mech 3.0 chemical kinetic mechanisms and detailed transport properties. The measured flame front position, temperature, and velocity of the stoichiometric CH{sub 4}/CO/air flames are closely predicted by the numerical calculations. Detailed analysis of the calculated chemical kinetic structures reveals that as the CO content in the fuel is increased from 0% to 80%, CO oxidation (R99) increases significantly and contributes to a significant level of heat-release rate. It is also shown that the laminar burning velocity reaches a maximum value (57.5 cm/s) at the condition of 80% of CO in the fuel. Based on the results of sensitivity analysis, the chemistry of CO consumption shifts to the dry oxidation kinetics when CO content is further increased over 80%. Comparison between the results of computed laminar burning velocity, flame temperature, CO consumption rate, and sensitivity analysis reveals that the effect of CO addition on the laminar burning velocity of the stoichiometric CH{sub 4}/CO/air flames is due mostly to the transition of the dominant chemical kinetic steps. (author)

• OSTI ID: 21137921
• Journal Information: Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 2 Vol. 156; ISSN CBFMAO; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
AIR
Blended fuels
CARBON MONOXIDE
COMBUSTION KINETICS
COMBUSTION PROPERTIES
COMPARATIVE EVALUATIONS
CONSUMPTION RATES
HEAT LOSSES
JETS
LAMINAR FLAMES
METHANE
Numerical simulation
OXIDATION
Premixed opposed-jet flames
SENSITIVITY ANALYSIS
SIMULATION
STOICHIOMETRY
VELOCITY