TY - JOUR
T1 - The porous-plug burner
T2 - Flame stabilization, onset of oscillation, and restabilization
AU - Kurdyumov, Vadim N.
AU - Matalon, Moshe
N1 - Funding Information:
V.K. acknowledges the support of the Ramon y Cajal Programm and the MEC under Project S-0505/ENE/0229. M.M. acknowledges the support of the U.S. National Science Foundation under Grants DMS-0405129 and CBET-0552140.
Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2008/4
Y1 - 2008/4
N2 - In recent studies of edge-flames it was found that when the characteristic gas velocity exceeds a critical value the flame often undergoes spontaneous oscillations. The oscillations are amplified as the flow rate increases, reaching a maximum amplitude, and then decrease with further increasing flow rate until the flame restabilizes. In this paper we examine the concept of flame restabilization in a simpler but related problem-the planar premixed flame on a porous-plug burner-which is amenable to a full stability analysis. We show the dependence of all possible steady states on the relevant parameters, including the mass flow rate, the effective Lewis number of the mixture, the overall activation energy of the chemical reaction, and the extent of heat release. A linear stability analysis is then carried out to examine whether these steady states are stable to small disturbances. The analysis determines the critical conditions for the onset of instability, as well as the nature of the instability. In particular, we show that by decreasing the mass flow rate, the flame, which is at first stable, starts to oscillate back and forth for a limited range of gas velocities but is then restabilized by further decreasing the mass flow rate. We also show that the properties of the plug, such as the thickness of the plate and its porosity, play a significant role in flame stabilization.
AB - In recent studies of edge-flames it was found that when the characteristic gas velocity exceeds a critical value the flame often undergoes spontaneous oscillations. The oscillations are amplified as the flow rate increases, reaching a maximum amplitude, and then decrease with further increasing flow rate until the flame restabilizes. In this paper we examine the concept of flame restabilization in a simpler but related problem-the planar premixed flame on a porous-plug burner-which is amenable to a full stability analysis. We show the dependence of all possible steady states on the relevant parameters, including the mass flow rate, the effective Lewis number of the mixture, the overall activation energy of the chemical reaction, and the extent of heat release. A linear stability analysis is then carried out to examine whether these steady states are stable to small disturbances. The analysis determines the critical conditions for the onset of instability, as well as the nature of the instability. In particular, we show that by decreasing the mass flow rate, the flame, which is at first stable, starts to oscillate back and forth for a limited range of gas velocities but is then restabilized by further decreasing the mass flow rate. We also show that the properties of the plug, such as the thickness of the plate and its porosity, play a significant role in flame stabilization.
KW - Flat flame
KW - Oscillations
KW - Porous-plug burner
KW - Restabilization
KW - Stabilization
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U2 - 10.1016/j.combustflame.2007.07.003
DO - 10.1016/j.combustflame.2007.07.003
M3 - Article
AN - SCOPUS:40749112710
SN - 0010-2180
VL - 153
SP - 105
EP - 118
JO - Combustion and Flame
JF - Combustion and Flame
IS - 1-2
ER -