Semi-empirical correlations for predicting hot gas layer temperature in pre-flashover compartment fires considering fire source location

Abstract

A series of numerical experiments have been carried out through a CFD code, namely Fire Dynamics Simulator (FDS), to analyze the influence of the fire heat source location (transversal, longitudinal and vertical positions) on the hot gas layer temperature (HGLT) in pre-flashover compartment fires. Knowing the HGLT helps engineers to predict the onset of flashover and to design fire safety systems, which give more time for evacuation procedures. Using these numerical data, and based on an energy balance on the upper layer, new semi-empirical correlations were developed to predict the HGLT in pre-flashover compartment fires, as a function of the fire source location, heat release rate, ventilation factor, surface area, effective heat transfer coefficient and ambient thermal properties. As an external validation of the newly developed correlations, their outcomes were tested against several sets of experimental data available in the literature, showing a good agreement. So, it is concluded that these improved correlations are capable to predict the HGLT for different pre-flashover fire scenarios, accounting to the position where the fire started.