TY - JOUR
T1 - Effect of Lewis number on flame propagation through vortical flows
AU - Kagan, L.
AU - Sivashinsky, G.
N1 - Funding Information:
The authors gratefully acknowledge the support of the U.S.–Israel Binational Science Foundation (Grant 2002008), the German-Israel Foundation (Grant G-695-15.10/2001), the Israel Science Foundation (Grants 67-01 and 278-03), and the European Community Program RTN-NPRN-CT-2002-00274. The numerical simulations were performed at the Israel Inter University Computer Center.
PY - 2005/8
Y1 - 2005/8
N2 - The premixed gas flame spreading through an array of large-scale vortices is studied numerically. It is found that the flame speed is a nonmonotonic function of the stirring intensity. At sufficiently low Lewis numbers (Le<1) the system becomes bistable with a hysteretic transition between possible propagation modes. In the presence of volumetric heat losses the stirring invariably promotes extinction (reduces the flammability limits), provided Le>1. At Le<1 this holds only for sufficiently strong stirring, whereas moderate stirring actually expands the flammability limits. At Le>1 the deficient reactant is fully consumed up to the very quenching point. At Le<1, prior to the total extinction, part of the deficient reactant escapes the reaction zone and remains unconsumed.
AB - The premixed gas flame spreading through an array of large-scale vortices is studied numerically. It is found that the flame speed is a nonmonotonic function of the stirring intensity. At sufficiently low Lewis numbers (Le<1) the system becomes bistable with a hysteretic transition between possible propagation modes. In the presence of volumetric heat losses the stirring invariably promotes extinction (reduces the flammability limits), provided Le>1. At Le<1 this holds only for sufficiently strong stirring, whereas moderate stirring actually expands the flammability limits. At Le>1 the deficient reactant is fully consumed up to the very quenching point. At Le<1, prior to the total extinction, part of the deficient reactant escapes the reaction zone and remains unconsumed.
KW - Flame-flow interaction
KW - Flammability limits
KW - Turbulent flames
UR - http://www.scopus.com/inward/record.url?scp=22844445707&partnerID=8YFLogxK
U2 - 10.1016/j.combustflame.2005.03.010
DO - 10.1016/j.combustflame.2005.03.010
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AN - SCOPUS:22844445707
SN - 0010-2180
VL - 142
SP - 235
EP - 240
JO - Combustion and Flame
JF - Combustion and Flame
IS - 3
ER -