Comments on the role of leakages in field modelling of under-ventilated compartment fires

The CFX general-purpose Computational Fluid Dynamics software has been tested against a compartment fire experiment performed by the Home Office. The experiment involved heptane pool fires, of about 10 MW unconfined output, in a leaky compartment having a volume of about 600 m(3). The building was nominally sealed for the first 5 min of the fire, at which point various combinations of doors and vents were opened. Preliminary computations predicted a collapse of the thermal stratification during the 'sealed' stage, in contradiction with the observations. A subsequent sensitivity study showed that weak leakages can have a major influence on the fire dynamics, and reasonable predictions were only obtained when the leakage resistance locations and proportions were measured in some detail and modelled more carefully. These results should be of value to those involved in theoretical, experimental, and practical aspects of large compartment fires. (C) 1999 Elsevier Science Ltd. All rights reserved.