Experimental study on combustion characteristics of pool fires in a sealed environment

The results of a series of bench-scale pool fire experiments to explore the burning characteristics under a sealed
environment are presented in this work.Although the oxygen fraction in the space gradually decreases by
burning consumingin comparison to open conditions, the transient heat release rate can still be calculated using
the PER approach using the in-situ measured oxygen fraction. The dimensionless flame height can still be
calculated using the McCaffrey’s model for open conditions, but a greater coefficient should be used because the
flame burns in a ‘hunger’ mode when the oxygen fraction is low. The current non-sealed fire model for centerline
temperature rise of pool fires is unsuitable for the sealed environment: the centerline temperature rise decreases
more quickly than that predicted by Nasr’s model developed for cases with a limited ventilation in the middle
and later stages of the fire. A new engineering model has been developed in this study by curve fitting sealed fire
test results. Pagni’s law can still be suitable to describe the relationship between the frequency of flame oscillation
and the diameter of a pool fire in a sealed environment, but the modified coefficients are required.