On the influence of a fuel side heat-loss (“soot”) layer on a planar diffusion flame

Abstract

A model of the response of a diffusion flame (DF) to an adjacent heat loss or “soot” layer on the fuel side is investigated. The thermal influence of the “soot” or heat-loss layer on the DF occurs through the enthalpy sink it creates. A sink distribution in mixture-fraction space is employed to examine possible DF extinction. It is found that (i) the enthalpy sink (or “soot” layer) must touch the DF for radiation-induced quenching to occur, and (ii) for fuel-rich conditions extinction is possible only for a progressively narrower range of values of the characteristic heat-loss parameter, N R ΔZ R . Various interpretations of the model are discussed. An attempt is made to place this work into the context created by previous experimental and computational studies.