Research On Fire Behavior Of Large-scale Aviation Kerosene Pool Fire And Fire Suppression Efficiency Of High Pressure Water Mist

With the rapid development of China's civil aviation transportation,the demand for prevention and control of fire risks in the hangars is increasing.As an important place for civil aviation firefighting,aircraft hangar plays an important role in ensuring the normal operation of civil aviation and the fire safety of aircraft maintenance.At present,foam and rain sprinkler system is widely used in the fire control system in our country's hangar,but in the actual operation process,the foam and rain sprinkler system has the disadvantages of persistent organic pollution,high water loss risk of aircraft equipment,large amount of water consumption,low cooling heat absorption efficiency and discomfort for electric fire.Due to the efficient heat absorption cooling and extinguishing efficiency,the high pressure fine water mist can effectively extinguish the solid fire and the liquid fire.It is also suitable for electric fire and will not cause environmental pollution.At present,high pressure water mist fire extinguishing technology has been widely used in ships,archives and other places,but rarely used in large space such as hangar.In order to optimize the fire fighting system of the hangar,the applicability of the high-pressure water mist fire extinguishing technology in the hangar is studied.In view of the large space of the hangar and the large fire load of the aviation kerosene leakage,the experiment platform for fire behavior of the aviation kerosene pool and the high pressure water mist suppression are designed and built,then the experiments of large-scale aviation kerosene pool fire behavior and fire suppression efficiency of high pressure water mist are carried out.By measuring and analyzing the changes of flame temperature,heat flux,combustion time and oxygen concentration in the combustion process of aviation kerosene,the relationship between the area of oil pool and the thickness of the oil layer with the behavior characteristics of the aviation kerosene and oil fire is studied in this paper.Based on the research on the aviation kerosene pool fire above,combined with the top-spraying high pressure water mist,the simulation experiment of the large-scale square aviation kerosene pool fire is carried out in the large space,the effect of the water mist flow on the fire suppression efficiency of the pool fire is studied,and the mechanism of the fire suppression of water mist is discussed.The main conclusions of this paper are as follows:(1)The combustion of large-scale aviation kerosene pool fire in large space can be divided into three major phases:rapid growth phase,stable combustion phase and gradual decay phase.The larger the pool area,the greater the average burning rate,the stronger the heat radiation,the higher the flame temperature and the space temperature.Under the conditions of this experiment,when the area of the pool is 1m~2-3m~2,the combustion rate,the heat flux and the flame temperature of the aviation kerosene are linearly related to the area of the pool,however,the development of the flame temperature and heat radiation in the combustion process of the 4m~2 pool fire are restrained.(2)under the experimental space,the greater the thickness of the oil layer,the greater the range of the high temperature area above the pool fire,the longer the steady combustion time,the more heat radiation at the same position in the stable combustion phase,but the effect on the maximum temperature of the space and the temperature of the top space is not obviously.(3)The combustion of large-scale aviation kerosene pool fire in large space has little influence on the oxygen concentration,but the area of pool and the thickness of oil layer will increase the consumption of oxygen concentration.In addition,the increase of pool area and oil layer thickness will bring about the increase of average burning rate of pool fire.(4)Water mist can effectively shield the heat radiation,reduce the space temperature,shorten the combustion time,protect the space structure and restrain the development of pool fire.With the increase of pool area,the suppression effect of fixed flow water mist on pool fire gradually weakened.(5)The larger the flow of water mist,the stronger the ability to absorb heat and shield heat radiation,and the better the suppression effect.For the 4m~2 pool fire,the water mist produced by the nozzle of the flow coefficient K=1.0 is poor in the heat insulation of the experimental top space,and the top space temperature cannot be controlled in a relatively low state for a long time.The water mist produced by the nozzle of the flow coefficient K=2.5 is better to suppress the 4m~2 pool fire,which can continuously control the top space temperature at a safe level.