Title of article :
Comparison of structures of laminar methane–oxygen and methane–air diffusion flames from atmospheric to 60 atm
Author/Authors :
Joo، نويسنده , , Peter H. and Charest، نويسنده , , Marc R.J. and Groth، نويسنده , , Clinton P.T. and Gülder، نويسنده , , ضmer L.، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2013
Pages :
9
From page :
1990
To page :
1998
Abstract :
A combined experimental and numerical study was conducted to examine the structure of laminar methane–oxygen diffusion flames in comparison with methane–air flames. Soot measurements made in these flames indicated that the maximum soot yields of methane–air flames are consistently higher than methane–oxygen flames at all pressures. The maximum soot yield of the methane–oxygen flames reaches a peak near 40 atm and then starts decreasing as the pressure further increased. The maximum soot yield of the methane–air flames plateaus at about 40 atm and does not change much with further increases in pressure. Methane–oxygen flames display a distinct two-zone structure which is visible from atmospheric pressure up to 60 atm. The inner zone, similar to hydrocarbon-air diffusion flames, has a yellow/orange colour and is surrounded by an outer blue zone. This outer zone was shown to have a stratified structure with a very steep equivalence ratio gradient. The main reactions in this zone were shown to be the oxidation of hydrogen and carbon monoxide produced within the inner zone. The methane–air diffusion flames had a thin layer of blue outer zone at atmospheric pressure; however, this zone completely disappeared when the pressure was increased above atmospheric. The presence of the two-zone structure in the methane–oxygen flames was attributed to the intensified penetration of oxygen into the core flow. The higher diffusivities, steeper oxygen concentration gradients, and enhanced entrainment increase the transport of oxygen to the flame. As such, there is sufficient oxygen present near the base of the flame to support the diffusion flame in the inner zone of the methane–oxygen flames. The abundance of oxygen near the centerline, even in the lower portion of the flame, also promotes the oxidation of soot.
Keywords :
Oxy-fuel combustion , Methane–oxygen flames , High pressure diffusion flames , Soot formation at high pressures , Two zone flame structure
Journal title :
Combustion and Flame
Serial Year :
2013
Journal title :
Combustion and Flame
Record number :
2277006
Link To Document :
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