The Structure of the Blue Whirl: A Soot-Free Reacting Vortex Phenomenon
The Structure of the Blue Whirl: A Soot-Free Reacting Vortex Phenomenon
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Date
2017
Authors
Hariharan, Sriram Bharath
Advisor
Gollner, Michael J
Oran, Elaine S
Oran, Elaine S
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DRUM DOI
Abstract
Recent experiments have led to the discovery of the blue whirl, a small, stable
flame that evolves from a fire whirl, and burns typically sooty hydrocarbons without
producing soot. The distinct physical structure of the flame is investigated through
digital imaging techniques, which suggest that the transition and shape of the flame
may be influenced by vortex breakdown. The thermal structure of the blue whirl reveals
a peak temperature around 2000 K, and that most of the combustion occurs in a
relatively small, visibly bright vortex ring. The formation of the flame is shown to occur
over a variety of surfaces, including water and flat metal, all of which indicate that the
formation of the blue whirl is strongly influenced by the flow structure over the
incoming boundary layer. Finally, a schematic structure of the blue whirl is proposed,
based on the measurements presented here and previous literature on fire whirls and
vortex breakdown.