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Title: Numerical simulation and flight experiment on oscillating lifted flames in coflow jets with gravity level variation

Abstract

Characteristics of oscillating lifted flames have been investigated numerically and experimentally by varying the gravity level in coflow jets with propane fuel highly diluted with nitrogen. The results showed that the oscillation amplitude and frequency increased with gravity level. As the gravity level decreased, the oscillation ceased and stationary lifted flames were stabilized when the gravity level became smaller than a critical value. A flame blowout occurred at high gravity levels. The reason for this limited range of oscillation has been analyzed by considering the local characteristics of the propagation speed of tribrachial (triple) flame and axial velocity at the edges of lifted flames. Considerations of the maximum and minimum values of these two components with gravity level during the flame edge oscillation could successfully explain the lower bounds of oscillation accounting for the influences of buoyancy and flame curvature. The blowout at high gravity levels can be explained by the effect of buoyancies on burnt gas and on propane fuel in such a way that the stoichiometric contour near the flame zone became detached from the contour near the nozzle. Finally, the experiments by varying gravity level through the parabolic flights of an aircraft substantiated the overall behavior ofmore » the oscillating lifted flames. (author)« less

Authors:
; ; ;  [1]; ;  [2]
  1. School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of)
  2. Division of Mechanical Science, Hokkaido University, Sapporo 060-8628 (Japan)
Publication Date:
OSTI Identifier:
20727301
Resource Type:
Journal Article
Resource Relation:
Journal Name: Combustion and Flame; Journal Volume: 145; Journal Issue: 1-2; Other Information: Elsevier Ltd. All rights reserved
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; FLAMES; GRAVITATIONAL FIELDS; OSCILLATIONS; PROPANE; NITROGEN; STABILIZATION; FLAME PROPAGATION; VELOCITY

Citation Formats

Kim, J., Kim, K.N., Won, S.H., Chung, S.H., Fujita, O., and Takahashi, J.. Numerical simulation and flight experiment on oscillating lifted flames in coflow jets with gravity level variation. United States: N. p., 2006. Web. doi:10.1016/j.combustflame.2005.10.018.
Kim, J., Kim, K.N., Won, S.H., Chung, S.H., Fujita, O., & Takahashi, J.. Numerical simulation and flight experiment on oscillating lifted flames in coflow jets with gravity level variation. United States. doi:10.1016/j.combustflame.2005.10.018.
Kim, J., Kim, K.N., Won, S.H., Chung, S.H., Fujita, O., and Takahashi, J.. Sat . "Numerical simulation and flight experiment on oscillating lifted flames in coflow jets with gravity level variation". United States. doi:10.1016/j.combustflame.2005.10.018.
@article{osti_20727301,
title = {Numerical simulation and flight experiment on oscillating lifted flames in coflow jets with gravity level variation},
author = {Kim, J. and Kim, K.N. and Won, S.H. and Chung, S.H. and Fujita, O. and Takahashi, J.},
abstractNote = {Characteristics of oscillating lifted flames have been investigated numerically and experimentally by varying the gravity level in coflow jets with propane fuel highly diluted with nitrogen. The results showed that the oscillation amplitude and frequency increased with gravity level. As the gravity level decreased, the oscillation ceased and stationary lifted flames were stabilized when the gravity level became smaller than a critical value. A flame blowout occurred at high gravity levels. The reason for this limited range of oscillation has been analyzed by considering the local characteristics of the propagation speed of tribrachial (triple) flame and axial velocity at the edges of lifted flames. Considerations of the maximum and minimum values of these two components with gravity level during the flame edge oscillation could successfully explain the lower bounds of oscillation accounting for the influences of buoyancy and flame curvature. The blowout at high gravity levels can be explained by the effect of buoyancies on burnt gas and on propane fuel in such a way that the stoichiometric contour near the flame zone became detached from the contour near the nozzle. Finally, the experiments by varying gravity level through the parabolic flights of an aircraft substantiated the overall behavior of the oscillating lifted flames. (author)},
doi = {10.1016/j.combustflame.2005.10.018},
journal = {Combustion and Flame},
number = 1-2,
volume = 145,
place = {United States},
year = {Sat Apr 15 00:00:00 EDT 2006},
month = {Sat Apr 15 00:00:00 EDT 2006}
}