Structures and stabilization of low calorific value gas turbulent partially premixed flames in a conical burner

Journal Article · Thu Apr 15 00:00:00 EDT 2010 · Experimental Thermal and Fluid Science

DOI:https://doi.org/10.1016/J.EXPTHERMFLUSCI.2009.10.011· OSTI ID:21285681

Yan, B; Liu, C ^[1]; Li, B; Sun, Z W; Li, Z S; Alden, M ^[2]; Baudoin, E; Bai, X S ^[3]; Chen, G ^[1]; Mansour, M S ^[4]

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1. Faculty of Environmental Science and Engineering, Tianjin University, 300072 Tianjin (China)
2. Division of Combustion Physics, Lund University, 221 00 Lund (Sweden)
3. Division of Fluid Mechanics, Lund University, 221 00 Lund (Sweden)
4. Cairo University, Natl Inst Laser Enhanced Sci., Cairo (Egypt)

Experiments are carried out on partially premixed turbulent flames stabilized in a conical burner. The investigated gaseous fuels are methane, methane diluted with nitrogen, and mixtures of CH{sub 4}, CO, CO{sub 2}, H{sub 2} and N{sub 2}, simulating typical products from gasification of biomass, and co-firing of gasification gas with methane. The fuel and air are partially premixed in concentric tubes. Flame stabilization behavior is investigated and significantly different stabilization characteristics are observed in flames with and without the cone. Planar laser induced fluorescence (LIF) imaging of a fuel-tracer species, acetone, and OH radicals is carried out to characterize the flame structures. Large eddy simulations of the conical flames are carried out to gain further understanding of the flame/flow interaction in the cone. The data show that the flames with the cone are more stable than those without the cone. Without the cone (i.e. jet burner) the critical jet velocities for blowoff and liftoff of biomass derived gases are higher than that for methane/nitrogen mixture with the same heating values, indicating the enhanced flame stabilization by hydrogen in the mixture. With the cone the stability of flames is not sensitive to the compositions of the fuels, owing to the different flame stabilization mechanism in the conical flames than that in the jet flames. From the PLIF images it is shown that in the conical burner, the flame is stabilized by the cone at nearly the same position for different fuels. From large eddy simulations, the flames are shown to be controlled by the recirculation flows inside cone, which depends on the cone angle, but less sensitive to the fuel compositions and flow speed. The flames tend to be hold in the recirculation zones even at very high flow speed. Flame blowoff occurs when significant local extinction in the main body of the flame appears at high turbulence intensities. (author)

• OSTI ID: 21285681
• Journal Information: Experimental Thermal and Fluid Science, Vol. 34, Issue 3; Conference: Sixth Mediterranean Combustion Symposium, Corsica (France), 7-11 Jun 2009; Other Information: Elsevier Ltd. All rights reserved; ISSN 0894-1777
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
09 BIOMASS FUELS
METHANE
FLAMES
CARBON DIOXIDE
CONES
LARGE-EDDY SIMULATION
AIR
HYDROGEN
MIXTURES
NITROGEN
BURNERS
STABILIZATION
CHEMICAL COMPOSITION
CARBON MONOXIDE
ACETONE
JETS
VELOCITY
HYDROXYL RADICALS
BLOWOFF
STABILITY
FLAME EXTINCTION
TURBULENCE
Low calorific gas flames
Partially premixed flames