Comprehensive Modeling of Turbulent Flames With the Coherent Flame-Sheet Model—Part I: Buoyant Diffusion Flames

Abstract

A modified version of the computational fluid dynamics code KIVA-II was used to model the transient behavior of buoyant turbulent diffusion flames burning in still air. Besides extensions to the range of permitted boundary conditions and the addition of buoyancy terms to the turbulence model, KIVA-II was augmented by a version of the coherent flame-sheet model, Tesner’s soot generation model, Magnussen’s soot oxidation model, and an implementation of the discrete transfer radiation model that included both banded and continuum radiation. The model captured many of the features of buoyant turbulent flames. Its predictions supported experimental observations regarding the presence and frequency of large-scale pulsations, and regarding axial distributions of temperature, velocity, and chemical species concentrations. The radial structure of the flame was less well represented. The axial radiative heat flux distribution from the flame highlighted deficiencies in the soot generation model, suggesting that a model of soot particle growth was required.