Effects of Gas Composition and Flame Sheathing on the Spatial Velocity Profiles of Laminar Analytical Acetylene Flames.
INDIANA UNIV AT BLOOMINGTON DEPT OF CHEMISTRY
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A recently developed technique has been employed to map the spatial rise velocity profiles horizontal and vertical of commonly used laminar analytical flames and to determine the influence on the profiles of fuel-to-oxidant ratio and the presence of a flame sheath. The rise velocities for fuel-rich, lean, and stoichiometric flames were found to differ substantially, the entire profile being greatest for the fuel-rich condition and lowest for the fuel-lean flame. In addition, the change in rise velocity with the addition of a solid quartz tube or gas N2 sheath was studied. The following sheath, at several different flow rates, affected each rise velocity profile principally by altering atmospheric entrainment and thereby changing secondary combustion in the flame. In contrast, a solid quartz tube used as a sheath produces an additional increase in the entire velocity profile of each flame, since it constrains gas expansion to the direction of flame propagation. The degree to which the velocity of each flame is affected by a sheath is strongly influenced by fuel-to-oxidant ratio. Author