Analytical Approach for Predicting Effects of Vitiated Air on the Mass Loss Rate of Large Pool Fire in Confined Compartments

The aim of this study is to determine the vaporization rate of an under-ventilated pool fire in a closed environment. A theoretical model that allows the burning rate of fuels to be determined for compartment fires under vitiated conditions is presented. The radiative and convective components of the heat flux from the flame to the pool surface are both evaluated and related to the ambient oxygen mass fraction. The model was first compared with the empirical correlation determined by Peatross and Beyler [1] before being applied to pool fires using heptane and PMMA as fuels in a small-scale apparatus. The global model presented here was then implemented in the CFD code ISIS and was validated against experiments involving a hydrogenated tetra-propylene pool fire test in a confined and mechanically ventilated compartment. It is shown that the model is able to correctly predict the fuel mass loss rate and provides a reasonable assessment of the heat flux from the flame to the pool surface.