Interaction of Lewis number and heat loss effects for a laminar premixed flame propagating in a channel

A thermo-diffusive model has been used to investigate the interaction of non-unity Lewis number and heat loss for laminar premixed flames propagating in a channel. A coordinate system moving with the flame has been used to immobilize the flame within the computational domain. At Lewis numbers significantly below unity in presence of high heat loss, tip opening near the centerline and dead space near the wall are simultaneously observed, that gives rise to a multicellular flame with "funnel-like" shape. At low Lewis numbers for fluid flow opposing the flame motion, increase in heat loss leads to a transition from inverted "mushroom" to "funnel-shaped" flame. The heat loss has a stronger effect for fluid flows opposing the flame motion than for fluid flows aiding the flame motion. For Lewis numbers above unity, the dependence of reaction rate on Lewis number gets reversed as heat loss increases from zero to a finite value. (C) 2007 Elsevier Masson SAS. All rights reserved.