CFD Modeling of Air Vitiation and Flame Extinction in Poorly-Ventilated Compartment Fires

摘要

The present study is aimed at evaluating the combustion modeling capability of an advanced Computational Fluid Dynamics (CFD) solver, called the Fire Dynamics Simulator (FDS), for under-ventilated compartment fire applications. FDS is developed by the National Institute of Standards and Technology (NIST), USA, and features in its most recent release a new flame extinction sub-model that describes air vitiation and associated oxygen starvation effects. This sub-model is here tested via detailed comparisons with an experimental database developed at the University of Maryland. The study considers four cases that correspond to different values of the fire room global equivalence ratio and are representative of strikingly different flame behaviors. The comparative tests serve to evaluate the general ability of FDS to describe the transition from over- to under-ventilated fire conditions, as well as the transition from extinction-free conditions to conditions in which the flame experiences partial or total quenching.