Intensification Mechanism Study On The Pool Fire Suppression With Water Mist

With the enhancement of people's environmental protection consciousness,some of the environmental pollution of the fire extinguishing agent has gradually been eliminated,the water mist fire extinguishing agent is attracting people's attention because of its unique advantages.At present,the research on water mist is mainly focused on the mechanism of atomization and water mist fire suppression.There are little researches to study the strengthening of water mist fire suppression at the initial stage.At present,the reason of the phenomenon of fire enhancement in the process of water mist fire suppression is mainly due to the following reasons: Firstly,Effect of air entrainment on flame in the fire suppression and the disturbance of the water mist to the flame.Secondly,boiling point depression caused by boiling phenomenon and the influence of boil over.Thirdly,early stage of water mist,effect of water gas reaction between water mist and carbon black.Fourthly,Effect of fuel splash caused by water mist impacting fuel on enhanced combustion.This paper is under the premise of improving water mist system in laboratory,taking the prediction of fire enhancement phenomenon as the starting point,the control variable method is adopted.Two groups of experiments were designed.The experiment was divided into water mist contacting oil in the pool or not.We used the side spray method in order to study the effect of fire intensification caused by water mist disturbing flame and mist entraining air while water mist doesn't contact the fuel.The direct injection method was used in order to observe the effect of water mist in the initial stage of fire enhancement.In the paper,the model of water mist dropping into the pool was built and the time that water mist began to hit the oil-pan was deduced according to the model.The experiments result indicates that:The disturbance of water mist to the flame and air entrainment can't cause the intensification phenomenon of the flame.But when the flame burns strongly,it will make the flame brighter.The phenomenon of the enhancement on the initial stage of water mist fire extinguishing mainly appears when droplets hit the fuel.In the initial stage of water mist spraying,the main reason of the phenomenon of fire enhancement is fuel splashing and vapor explosion caused by droplets dropping into oil-pan.The intensity of fire enhancement has a great relationship with the rate of fuel gasification.