Effects of Nozzle Type and Injection Pattern on Evaporative Cooling Performance of Water Mist Fire Suppression Systems

This work was focused on assessing the effects of nozzle type and injection pattern on the energy extraction and evaporative cooling of a hot environment in water mist fire suppression systems. For this aim, a simple two dimensional computational code was developed. Mass, momentum and energy conservation of droplets were calculated in Lagrangian coordinate. Results of the code have been verified against someother reported data and a good agreement was found. In this research, Rosin-Rammler and Chi-square distribution function have been considered in order to simulate the droplet size distribution in hollow-cone and full-cone nozzles. Results showed that using the hollowcone spray significantly improves the evaporative characteristics of water mist systems. This is due to the small SMD of droplets at the hole of hollow cone nozzles. At similar SMD at the nozzle exit the effect of injection pattern on evaporative cooling power of water mist spray is not significant