Concentration measurements of selected hydrocarbons in methane/air partially premixed flames using gas chromatography

• Published in: International journal of thermal sciences Vol. 44; no. 11; pp. 1078 - 1089
• Main Authors: Mishra, T.K., Datta, A., Mukhopadhyay, A.
• Format: Journal Article
• Language: English
• Published: Paris Elsevier Masson SAS 01-11-2005; Elsevier
• Subjects: Applied sciences; Combustion of gaseous fuels; Combustion. Flame; Concentration measurement; Energy; Energy. Thermal use of fuels; Equivalence ratio; Exact sciences and technology; Gas chromatography; Partially premixed flame; Theoretical studies. Data and constants. Metering; Concentration measurement; Gas chromatography; Equivalence ratio; Partially premixed flame; Methane; Hydrocarbon; Ethylene; Flame structure; Premixed flame; Ethane; Acetylene
• ISSN: 1290-0729; 1778-4166
• DOI: 10.1016/j.ijthermalsci.2005.03.014

Concentrations of selected hydrocarbons (viz. CH
4, C
2H
6, C
2H
4 and C
2H
2) have been measured in CH
4/air partially premixed flames for different primary mixture equivalence ratio (
ϕ) and primary jet velocity using gas chromatography. Visual observations of the flames are also made using digital photography. An axi-symmetric, co-flowing burner is placed on a traversing stage and a quartz probe is used for the collection of the gas sample by placing it at appropriate locations with respect to the burner. The double flame structure is observed with the increase in the premixing air with the fuel. At a high premixing air, the inner flame turns from blue to a greenish one. Hydrocarbons are detected only inside the inner flame structure of the partially premixed flames at all equivalence ratios studied and the concentrations of the non-fuel hydrocarbons are much less than in the non-premixed flames at most of the locations. The peak C
2H
6 and C
2H
4 concentrations are found to be the maximum in a partially premixed flame with an intermediate
ϕ, while peak C
2H
2 concentration continually decreases with the decrease in
ϕ. The partial premixing decreases the radial transport of species at lower elevations mainly because of the high axial velocity of the primary jet. At higher elevations within the inner flame the radial distribution of C
2H
4 and C
2H
2 concentrations show the peak value to exist at the centerline.