Magnetically induced flame flickering

Legros, G., Gomez, T., Fessard, M., Gouache, T., Ader, T., Guibert, P., Sagaut, P. and Torero, J. L. (2011) Magnetically induced flame flickering. Proceedings of the Combustion Institute, 33 1: 1095-1103. doi:10.1016/j.proci.2010.06.124

Author Legros, G.
Gomez, T.
Fessard, M.
Gouache, T.
Ader, T.
Guibert, P.
Sagaut, P.
Torero, J. L.
Title Magnetically induced flame flickering
Journal name Proceedings of the Combustion Institute   Check publisher's open access policy
ISSN 1540-7489
Publication date 2011
Year available 2011
Sub-type Article (original research)
DOI 10.1016/j.proci.2010.06.124
Open Access Status
Volume 33
Issue 1
Start page 1095
End page 1103
Total pages 9
Place of publication Philadelphia, PA United States
Publisher Elsevier Inc.
Collection year 2011
Language eng
Subject 2210 Mechanical Engineering
1500 Chemical Engineering
1606 Political Science
Abstract This paper addresses a still unknown effect of a high downward gradient of the square of the magnetic flux density on a laminar methane diffusion flame established over an axisymmetric co-flow burner. Because the magnetic force is expected to act mainly on paramagnetic oxygen, a parametric study varying the co-flowing stream oxygen content, the oxidizer velocity and the magnitude of the gradient of the square of the magnetic flux density was performed. CH radicals spontaneous chemiluminescence was captured to track the flame sheets. Despite a low Reynolds number at the fuel exit and oxidizer flow velocities slightly larger than the fuel exit velocity, the flame flickering was triggered by downward gradients of the square of the magnetic flux density of magnitudes from 0.4 and 1.4 T2/m for O2 contents of 0.75 and 0.55, respectively. This flickering is shown to result from an axisymmetric mode of a convective instability. Qualitative speculations based on previous works suggest that the magnetic body force may alternately strengthen buoyancy and shear stress, therefore hastening the instability onset. Indeed, at relatively low Grashof numbers, a region of flickering conditions shows up and grows with a magnetic Reynolds number. The sensitivities of the flickering frequency and amplitude are finally addressed, namely showing that over the investigated range of parameters the frequency spreads from 10.5 to 14 Hz.
Keyword Diffusion flame
Magnetic field
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Civil Engineering Publications
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Created: Fri, 08 Aug 2014, 10:44:04 EST by Julie Hunter on behalf of School of Civil Engineering