An Experimental and Modeling Study on the Effect of Wall Opening Location on the Under-Ventilated Compartment Fire

Abstract

An experimental and modeling study was carried out to investigate the effect of wall opening location on the mass flow rates of gases through the opening and the associated fire phenomena, such as compartment temperature, projected flame height through the opening, and the heat release rates inside and outside the compartment. A 0.3 m by 0.3 m opening was placed at three different elevations—bottom, middle, and top—of a narrow end wall of a 0.8 m by 1.2 m by 0.8 m (H) compartment. A propane gas burner was used to provide four different fire sizes in the compartment: 90, 110, 130, and 150 kW. The existing correlations for mass flow rates and heat release rates generally do not include the wall opening location as a variable and are functions of only the opening area and height. Based on the experimental and modeling analysis, it is found that the wall opening location affects the internal and external fire phenomena. Two fundamental factors, K and O, are introduced to explain the effect quantitatively. Factor K is the ratio of the air inflow predicted by Fire Dynamics Simulator (FDS) to the existing correlation (0.5AoHo), and Factor O is the ratio of the oxygen consumption rate in the compartment to the oxygen flow rate into the compartment, indicating combustion efficiency. Factor K ranges from 0.78 to 0.94, and O ranges from 0.67 to 0.85 for different opening locations, which suggests that the existing correlations may overestimate the amount of airflow to and the combustion efficiency within the compartment.