| With the vigorous development of economy and society and continuous innovation in science and technology,China's urban infrastructure construction requirements are gradually increasing.In order to save a large amount of urban land resources and improve the use efficiency of urban road pipelines,the construction of urban integrated pipe corridors has become the main way of urban pipeline construction in China.The construction of the composite pipe gallery brings great convenience to the residents but also brings fire risk.This paper analyzes the cause of cable fire and expounds the cause of fire under different circumstances.In view of the fire characteristics of the cable cabin of the composite pipe gallery,the applicability of various automatic fire extinguishing systems in the composite pipe gallery was compared and analyzed,and reasonable and effective fire extinguishing systems were set up to prevent and control the fire development.This paper chooses the high pressure water mist fire extinguishing system with energy saving and environmental protection,good fire extinguishing effect and high cost performance.The comprehensive pipe corridor experiment model was built and the real fire experiment was carried out.Set two groups of experiment condition,water mist nozzle vertically installed 90° and 45° nozzle side,which is injection and side injection,Analyze the extinguishing efficiency of high pressure water mist extinguishing system to cable fire by changing the installation Angle of sprinkler head.The experimental results show that in the fire,45° installed sprinkler lateral and vertical,compared to 90° installed sprinkler can greatly shorten the time put out the fire,better control and lower the temperature in the fire.On the basis of the experiment,the Pyrosim software of numerical simulation was used to establish the experimental model.The comparison and analysis of the two data show that the variation law of the measured temperature curve is consistent with the numerical simulation results.The results show that the numerical simulation Pyrosim software is suitable for the study of fire hazard of integrated pipe and corridor cables.This paper studies the comprehensive pipe gallery in a certain area and establishes a numerical model of the comprehensive pipe gallery in a fire prevention zone.The fire extinguishing effect was studied by changing the droplet size,flow coefficient,atomization Angle,nozzle spacing and nozzle installation Angle.The optimal design scheme of sprinkler head in water mist extinguishing system is selected to provide theoretical basis for the selection of sprinkler head in practical engineering.Simulation analysis results show that:(1)water mist with particle size of 100?m can completely submerge,compared with the fine water mist fire extinguishing system with particle size of 200?m and 300?m,the fire extinguishing,cooling and smoke removal effect is better.It is recommended to choose the fine water mist fire extinguishing system with particle size of 100?m.(2)as the flow coefficient increases,the extinguishing efficiency of water mist increases.When the flow coefficient is 1.5 and 1.7,the fire extinguishing efficiency is ideal.Considering comprehensively,it is recommended to choose the water mist fire extinguishing system with the flow coefficient of 1.5.(3)the spray cone Angle 120° of water mist compared with other spray cone Angle,extinguishing time shortest and cooling dust effect very good,recommended spray cone Angle is 120° of fine water mist fire extinguishing system.(4)when the sprinkler heads are spaced at 1m,2m and 3m,the fire can be successfully extinguished.Considering water consumption and pipeline pressure,it is recommended to use 2m or 3m nozzle spacing.(5)there is little difference in the vertical and lateral installation sprinkler efficiency,but the side spray has better temperature control and cooling effect.It is recommended to adopt the side installation of sprinkler head. |
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