受限空间脉冲细水雾系统关键参数试验与数值模拟研究

为了研究脉冲细水雾的关键参数，采用FDS软件对不同周期的脉冲细水雾熄灭受限空间油盘火进行了数值模拟，分析了脉冲周期的优化设置、细水雾的灭火效果和灭火机理。根据模拟结果进行参数设置，建立了脉冲细水雾试验平台，对脉冲细水雾熄灭不同尺寸油盘火进行了试验研究，并与数值模拟结果对比。研究表明:脉冲细水雾的最佳周期应满足喷头开启时间接近雾滴降至燃料表面的时间，暂停时间接近雾滴的生存时间；脉冲细水雾能熄灭不同尺寸火源，其灭火效果优于连续细水雾，雾滴蒸发效率更高，灭火机理为水雾蒸发稀释氧气而窒息灭火。

Experimental and numerical simulation study on key parameter of pulse water mist system in confined space

To study the key parameter of pulse water mist, the numerical simulation on extinguishment of oil pan fire by pulse water mist with different cycles in a confined space was carried out by using FDS software, then the optimization setting of pulse cycle and the extinguishing effect and mechanism of water mist were analyzed. The parameters setting was conducted according to the simulation results, and an experimental platform of pulse water mist was built. The experimental study was conducted on the extinguishment of oil pan fire with different sizes by pulse water mist, and the results were compared with the results of numerical simulation. It showed that the optimum cycle of pulse water mist should satisfy that the opening time of nozzle is close to the time for droplets to drop on the surface of fuel, and the pause time is close to the life time of droplets. The pulse water mist can extinguish the fire sources with different sizes, and its extinguishment effect is better than that of continuous water mist. It has a higher droplets evaporation efficiency, and the extinguishment mechanism is the smothering extinguishment through oxygen dilution by the evaporation of water mist.