A Tractable Solution for Engineering Calculations on Buoyancy Dominated Turbulent Non-Premixed Flames

Abstract

The modelling of molecular species and smoke concentrations in turbulent buoyant intermediate free pool and enclosure fires is described. The numerical model solves the time-dependent reactive flow, Navier-Stokes equations, coupled with submodels for soot formation and thermal radiation transfer. A comparison is performed, and differences are discussed between the values of the temperature, velocity, carbon monoxide and smoke concentrations in the fire from the current study and the literature. The current modeling indicates that CO generation is relatively independent of position in the overfire region, and is correlated solely as a function of mixture fraction. No link between the soot concentration and the mixture fraction is found, which suggests that soot formation in the fires is fundamentally controlled by the transient phenomena. For a free pool-like fire, the computed peak temperature, velocity and CO concentration differ from the experimental values by less than 15%. The soot volume fraction differs significantly from the experimental data only in the fuel-lean, thermal plume region.