Effect of reduced pressure on burning dynamics of fire whirls

Abstract

The fire whirl is an intensification of combustion, but its pressure effect is still unknown. In this study, small-scale fire whirls (<10 kW) were generated by square enclosures with slits inside a large low-pressure chamber. As the pressure decreases, the fire whirl becomes bluer, and the burning rate decreases linearly at a rate five times faster than the pool fire. Thus, the hazard of fire whirl drops significantly at the reduced pressure. Unlike the flame height of pool fire increasing with pressure, the flame height of fire whirl is almost insensitive to the pressure due to the competition between burning rate and whirling airflow.