Efficiency of water mist on fire suppression: A numerical study

Water mist fire suppression systems which use relatively small droplets of water with high injection pressure are increasingly being used in wider applications because of its greater efficiency, low flooding damage and low toxicity. However, the performance of the system significantly relies on the water mist characteristics and fire environment and it requires better understanding of fire suppression mechanism of water mist. In the present study, computational fluid dynamics simulations were carried out to investigate the interactions between water mists and fire fields. The gas phase was prepared with natural convection heat transfer model for incompressible ideal case and then the effects of water mist characteristics on cooling capabilities were numerically investigated upon the basis of the predetermined temperature field. For the simulation of water mist behavior, Lagrangian discrete phase model was employed by using a commercial code, FLUENT. Fire suppression efficiency based on different water mist characteristics such as droplet sizes, injection angles, water flow rates and fire types was investigated.