Effects of heat release and flame distortion in the transverse fuel jet

Abstract

An analytical model for a chemically reacting transverse jet is applied to the situation in which effects of compressibility and heat release are important, as in turbulent diffusion flames deflected by an air stream. This model examines the dynamics of the vortex pair structure observed to dominate the flowfield, a structure which causes the combustion process to proceed in a bifurcated flame. Heat release is represented through local source terms coincident with reacted cores of combustion products, and vorticity is represented in terms of a nearfield component of vortex strength (arising from the crossflow) and a farfield component of vortex strength (arising from the fuel jet impulse). Results indicate that the heat release in the reaction acts to reduce the degree of crossflow penetration by the flame, in addition to reducing the strength of the vortices and the magnitude of the vortex spacing. Buoyancy is found to play a lesser role in flame development than that of the jet momentum for the jet-to-crossflow velocity ratios considered. Based on comparisons with experimental results, the amount of entrained oxidizer required for the reaction is found to be lower than that required in an isothermal reaction.