| During the past several years, water mist technology has been developed and regarded as a promising substitute since it can extinguish the fire quickly with little water and at the same time without damage to environment and protect objects. Generally water mist is defined as fine water droplets for which the droplet diameter at the thickest part on the surface 1 meter away from the nozzle, Dv0.99, is less than 10001μm at the minimum design pressure. Water mist can be used to suppress electrical fire, and it can also find wide applications in the protection of special fires at high-tech and industrial locations such as computer room and aircraft cabin.Generally speaking, fine water mist is involved by one or several of the following fire suppression mechanisms: gas phase cooling, heat extraction from the fire, oxygen depletion near the fire and radiant heat attenuation. But the predominant extinguishment modes for water based fire suppression systems vary with the fire source and environment. Combustion of liquid fuel soaked in porous beds is a special category of liquid fuel combustion. Combustible liquid such as gasoline can diffuse into soil or other porous materials due to leakage from accidental spillage or automobile collision. If an external heat source is close to the fuel layer, ignition can be triggered and subsequent flame spread can occur over the surface. If the flame spread is not controlled in a proper way, severe loss of human life and property damage can occur. However, only a few studies have been carried out on this subject. Thus it has important effect on fire prevention and soil depollution to study fire suppression mechanism by fine water mist. This paper is to research on the interaction between fine water mist and liquid fuel soaked in porous beds flame which can help to deepen the understanding of water mist fire suppression mechanism.In the first chapter, the concept of water mist and the difference between water mist and other fire suppression agents were introduced. The mechanisms and effectors of water mist fire suppression technology were reviewed.In the second chapter, the characteristics of water mist were tested, including nozzle jet angle, water flow rate and water droplet diameter. Full evaporation times of water mist droplets were also estimated.In the third chapter, experimental studies were conducted to investigate the interaction of water mist with flames of ethanol fuels soaked in porous beds. The effects of nozzle jet pressure, fire preburn time and characteristics of porous materials on water mist extinguishing were presented. The experimental results show that the three effectors had important action on water mist fire suppression.Finally, the summary and the further suggestions were presented in the last chapter.
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