Influence of Complete Enclosure on Liquid Pool Fires

Abrtract

This work advances the area o f zone modeling by the development of a five-zone theoretical model with time-incrementing capabilities to predict the results of liquid pool methanol fires in a gas-tight enclosure. The model consists of a liquid pool fuel hed, a developed flame above the fuel bed, a plume on top of the flame, the enclosure walls, and an ambient gaseous medium between the enclosure walls and the flame-plume boundaries. It assumes a temperature dependent chemical equilibrium between the combustion products and evaporated fuel in the flame. It also dictates the energy feedback within each defined zone and predicts the temperatures (ambient gas. flame, and plume), the mass evaporation rate of the fuel, the total pressure. and the oxygen concentration within the enclosure. The early effects of oxygen concentration on a con-fined methanol fire are well established in this work through a comparison with an open methanol fire model. Initially the rising ambient gas temperature causes the mass evaporation rate of the fuel to increase. Eventually the dropping oxygen concenration reduces the mass evaporation rate through its influence on the mass air entrainment rate and the flame height. Tere is no evidence in the region of the maximum burning rate for the influence o f non-stoichiometric combustion.