不同喷射方式细水雾灭火效果的试验

细水雾的喷射方式对其灭火效果存在一定的影响。利用时间继电器控制细水雾灭火系统的启停,开展了连续式和脉冲式两种喷射方式的细水雾对开门与关门两种通风条件下不同燃料油池火分别进行抑制的试验研究。结果表明:在试验条件下,对于开门状态下连续式细水雾难以扑灭的汽油池火,脉冲式细水雾能显著提高灭火效果;对于连续式细水雾容易扑灭的柴油池火及关门状态下的汽油池火,脉冲式细水雾不能提高灭火效果,且灭火时间和用水量均有所增加;对于细水雾难以扑灭的酒精池火,连续式细水雾和脉冲式细水雾均未有效扑灭火焰。

Experimental study for the fire-suppressing effects via water mist in different discharge modes

The paper aims to investigate and identify the effects of different discharge modes of water mist on the fire suppression performance through a series of contrast fire suppression experiments with different liquid fuels,such as gasoline,diesel and alcohol in a continuous and cycling discharge water mist system.In the said fire suppression experiments,we have managed to use a time relay switchboard in an experimental cabin with and with no ventilation amenities.In the aforementioned experiments,we have made an analysis and gained enough data on the fire-extinguishing time,the smoke temperature,radiation,the total heat flux intensity and the oxygen and carbon monoxide concentration in the fire suppression process.The results we have gained from the experiments show that the water mist system in the cycling discharge mode can be expected to extinguish the gasoline pool fire effectively with the door open,which is unlikely to be extinguished by the continuous discharge mode.Nevertheless,it is necessary to increase the fire extinguishing time and water consumption in case for the gasoline pool fire suppression with the cycling discharge mode with the door closed and diesel pool fire to be stamped out quickly in a continuous discharge mode,whereas for the ethanol pool fire water mist suppression both the modes may not be efficient.Endothermic heat transfer in droplets dominates the fire suppression process with continuous water mist for pool fire combustion,which is independent of oxygen.Nevertheless,the heat transfer and the dynamic effect may both play critical roles in the fire suppression process in the cycling discharge mode.Therefore,since the smoke temperature,the heat radiation and even the total heat flux may all tend to decrease in a descending tendency,the water mist is likely to activate and fluctuate with the alternation of the water mist system.Thus,it can be concluded that the cycling discharge water mist system should be expected to improve the fire suppression efficiency and reduce water consumption to stamp out somewhat combustible liquid fuel or fuels with lower flash point in an open cabin,which can not be extinguished via the continuous discharge water mist system.