Turbulent Combustion and Thermal Radiation in a Massive Fire

摘要

This study was motivated by an actual large-scale fire of combustibles in open storage, where the fire growth and flame dynamics were greatly affected by the cross-wind. The objectives include development of the model and computer code for studying buoyant turbulent diffusion flames of large fires exposed to cross-winds in the open atmosphere, computer simulations of coherent flow structures in the wind-blown fire plume and of radiative heat fluxes both inside the flame and incident to remote targets. In the developed model, the large eddy simulation (LES) technique is applied for modeling the turbulent flame and thermal plume. In combustion modeling, the presumed probability density function approach is used, within the framework of fixture fraction formulation. Thermal radiation transfer is modeled using the Monte Carlo method, adopting either the weighted sum of gray gases (WSGG) approach or the gray media assumption. Coherent flow vortical structures in the fire plume and the radiative impact of the flame are analyzed through computer simulations and compared with the available experimental data. In special cases, the predicted radiative heat fluxes incident to both targets engulfed in fire and remote surfaces have been found to be in reasonable agreement with the empirical correlations and simple engineering approaches.