Experimental Investigation of Ventilation Effects on Combustion Efficiency and Heat Release Rate in Small-Scale Compartment Fires

A series of fire experiments were conducted in a 0.5 m × 0.5 m × 0.5 m room, and a single door-like opening was adopted. The height of the openings was 20 cm, and the width of the openings varied from 10 cm to 30 cm, with ventilation factors ranging from 0.0089 m5/2 to 0.0268 m5/2. The ventilation constant and combustion efficiency were studied and compared with those of other researchers. It was found that the so-called ventilation constant can hardly be a constant, and it varied greatly, around 0.357–0.436, at different ventilation conditions. The overall combustion efficiency varied greatly at different opening sizes and flow rates, and it was as low as 0.5, even when the flame was ejected.