A transient one-zone computer model for total flooding water mist fire suppression in ventilated enclosures

As water mist fire fighting systems become increasingly common, there is a need to transform the accumulated practical experience to quantitative models. As a contribution to this process, this paper proposes a transient one-zone computer model for total flooding water mist fire suppression in ventilated enclosures. The one-zone approach is based on the experimentally observed ability of the water sprays to mix the gas volume of the protected space. From this assumption, the model solves the time evolution of temperature, gas density, gas composition and water mist concentration inside the protected space. The model incorporates a detailed description of the liquid phase (mist droplets) and the evaporation process. The extinguishment of a hydrocarbon flame is predicted based on the adiabatic flame temperature concept. The possibilities and limitations of the model are demonstrated by validation against experimental data from large-scale machinery space fire suppression tests.