S. Ferraris

Large Eddy Simulation of the Backdraft Phenomenon and Its Mitigation in Compartment Fires with Different Opening Geometries

A sub-grid scale model for partially premixed combustion has been implemented into an existing LES code and applied to simulate turbulent deflagration in backdraft and its mitigation by watermist in a scaled-compartment with different vent geometries. The model is based on the coupling of independent approaches for non-premixed and premixed turbulent combustion, while the flame index concept was used to separate the two different combustion regimes. Simulations were conducted for the reduced scale tests of Weng and Fan (2002). Reasonable agreements have been obtained for species concentrations, total mass outflow and inflow rates, maximum pressure, and likelihood of the occurrence of the fireball outside the container. The numerical study has highlighted the mitigation effect of watermist by reducing the laminar burning velocity of the mixture and the influence of the end opening geometries on the occurrence of backdraft.

Large-eddy simulation of a large-scale methane pool fire

In this study a modified version of the Conditional Source Estimation (CSE) model has been developed. It is assessed on a diffusion flame (SANDIA Flame D) and a 1m diameter methane pool fire. In both cases it has been found that mean mass species concentration, temperature, scalar and velocity fields agree reasonably well with the experiments. The main goal of this paper is to prove the possibility of employing the CSE as a model of low computational cost for large fire simulations. The work also highlights the importance of soot and radiation models in large scale fires.