Ventilation effect on the fire behavior in a vehicle engine compartment

This study investigates the impact of ventilation, specifically modeled by a radiator fan, on heptane pool fires within a military ground vehicle engine compartment. Experiments were conducted in a 2.44 m3 scale-1 compartment with varying fan-generated inflow velocities, initial fuel thicknesses, and pan diameters. The primary objective is to comprehensively assess how ventilation conditions affect pool fire behavior, focusing on properties such as mass loss rate, heat release, temperature, and heat flux in both the boiling and steady stages. The results reveal that the boiling stage occurs at initial fuel thicknesses of 10 and 15 mm, allowing us to analyze the boiling-to-steady ratio. This ratio exhibits variation across parameters. For burning duration, the ratios range from 0.45 to 0.93, while for mass loss rate, the ratios range from 2.3 to 3.5. Regarding total heat flux, the ratios span from 2.5 to 4. The boiling-to-steady ratio for temperature varies by position: in the vertical tree, it ranges from 1.1 to 1.7; in the ceiling tree, it ranges from 2.2 to 2.9; and in the ceiling side tree, it ranges from 1.2 to 2.25. Ventilation influences the boiling-to-steady ratio. Increasing inflow velocity generally increases the ratio for burning duration and ceiling tree temperature while decreasing the ratio for mass loss rate. The impact of ventilation on other properties depends on pan diameter and initial fuel thickness.