Numerical simulatoin of poolfire suppression using water mist system investigating nozzle parameter effects

With recent developments in sprinkler technology, water mist system is becoming more and more useful in fire suppressions. The computational method is an efficient way to investigating effect of Nozzle parameter of water mists and optimize them. In this research, a open source fire dynamic simulator (FDS) is used to numerically investigating the different nozzle parameter on the fire suppression and extinguishment mechanism.The range of droplet size was determined based on the NFPA 750 standard. Extinguishing mechanisms in water mist systems and their effect on extingushing time and nozzle parameter such as droplet size, water flow rate and spray cone angle were investigated. The simulation concluded that droplet sizes I hollow cone angle smaller than 121 μm and larger than 600 μm were appropriate for fire extingushment. With a full cone angle nozzle and 1/5 flowrate compared with hollow cone nozzle, fire extingush time reduce from 26 second to 7.4 second. Spray cone angle in fine droplets does not much affect the duration of fire extinguishing, however, for large droplets, the desired result can be achieved by reducing the spary cone angle. So with recognition of nozze parameter and its effects on fire extingushing time could rich the optimum design.