Numerical simulation of water mist suppression effectiveness in different conditions

A numerical simulation with FDS was carried out for the interaction of water mist with pool fire.The extinguishing mechanism of water mist in different regions of fire plume and the influences of particle size distribution,velocity,spray angle were investigated.The results showed that particle size distribution had a great effect on fire extinguishment.When the droplet diameters were 100μm,the fire cannot be extinguished;when droplet diameters were in the range of 200~400μm,the fire was suppressed by water mist effectively and extinguished finally.In the extinguishing mechanisms,the surface cooling effect played a more important role than the gas-phase cooling effect and suffocation effect;At the same time,the velocity of the droplet also had a great effect on the effectiveness of fire extinguish;an important prerequisite for the fire extinguishment was that the water mist momentum should not be less than the fire's momentum;The water mist flux became smaller with the increase of spray angle,the increase of spray angle wasn't conducive to fire extinguishment.