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http://dx.doi.org/10.3795/KSME-B.2012.36.3.309

The Effects of Velocity and Concentration in the Oxidizer of Heptane Pool Fires on the Flame Stability  

Jeong, Tae-Hee (Dept. of Safety Engineering, Pukyoung Nat'l Univ.)
Lee, Eui-Ju (Dept. of Safety Engineering, Pukyoung Nat'l Univ.)
Publication Information
Transactions of the Korean Society of Mechanical Engineers B / v.36, no.3, 2012 , pp. 309-314 More about this Journal
Abstract
Flame flickering occurs mainly because of the buoyancy force for pool fires under ambient air. The cup-burner flame was used for experimental investigation of the effect of the oxidizer velocity on the gravitational instability. The results showed that the flickering frequency decreased with increasing oxidizer velocity. The frequency-buoyancy relation with nondimensional variables coincided with that of the buoyant flume and pool fires when the characteristic velocity was defined as the difference between the fuel and oxidizer velocities, which implies that the origin of the gravitational instability is the Kelvin-Helmholtz instability in the shear layer. The effect of the oxidizer composition on the instability was also examined through nitrogen dilution in the oxidizer stream. As the concentration of inert gas increased, the length of the blue flame increased and lift-off behavior was observed. The oscillation frequency was independent of the dilution ratio, but was related to the local flame structure.
Keywords
Pool Fire; Cup Burner; Burning Rate; Flame Stability;
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