摘要：This article is an attempt to reveal the fire extinguishing mechanism under the action of pulsed water mist system using the method of Large Eddy Simulation (LES). The fire extinguishing performances with continuous and pulsing discharge modes were numerically investigated by measuring gas temperature, oxygen concentration and fire-extinguishing time. The simulation results presented that the pulsed water mist has no obvious advantage over the continuous water mist in the open space, but has a considerable extinguishment performance by optimizing the interval of the pulsing discharge mode in the confined space. The optimum pulse interval was obtained. Moreover, the oxygen dilution effect of pulsed water mist plays an important role in fire extinguishment. The numerical simulations conducted in this work can provide global information on the fire-extinguishing time under different discharge modes as well as spatially-resolved information on the advantages of pulsed water mist extinguishment based on oxygen concentration and water vapor concentration. The results suggested that the best suppression performance of pulsed water mist was achieved when the oxygen concentration around the flame base was diluted. The above results can provide a significant reference for the optimal design of water mist fire suppression system.
关键词：Large Eddy Simulation ; Continuous and pulsing discharge ; Extinguishment performance ; Open space ; Confined space
