Research On Fire Simulation And Smoke Exhaust Mode Of Subway Station

The subway is a fast,punctual and environment-friendly mean of transportation.It has become an important way of solving traffic problems.Because of limited space and high density of personnel,it is difficult to exhaust smoke in subway stations.Fire accidents often cause a large number of casualties and damage.Therefore,it is important to study the optimization of smoke exhaustion to avoid casualties and reduce property losses.In the article,the FDS software was used to simulate the smoke exhaust mode based on the smoke extraction facilities of an island-type station.The research results can provide suggestions for station fire emergency evacuation plan and smoke system optimization.Station evacuation plan stipulates:When a fire occurs on the platform and the train does not arrive at the station,it is only necessary to open the station system to exhaust smoke.This paper simulates the smoke exhaustion effect of the large system when the middle position of the platform is on fire.The results show that it has some pressure to ensure the safe evacuation of personnel if only opening the large system.It is necessary to optimize the smoke exhaust mode.Therefore,this paper proposes a joint smoke extraction system for the station and the tunnel when platform fire occurs.According to the opening method about the fan,the shield door and the window,six specific optimization measures are proposed.Setting 6 operating modes in FDS,the simulation results are analyzed and compared from the flow field,the smoke,the height,the temperature,the visibility,CO and CO2.It is determined that when a fire occurs in the middle of the platform,the best mode is to " open the station system,open the shield door in the middle,close the shield doors at both ends and open the fans at the tunnel".In addition,this paper also studies the situation of train fire when the train arrives at the station.This paper sets 4 operating modes and comparts the effects of smoke exhaust about the fan at the rail top and the tunnel fan.The results show that opening the rail top exhaust is better than the opening the tunnel fan.This setting keeps the temperature and CO concentration values on the platform within a safe range in seven minutes.Therefore,it is suggested that the smoke exhaust system on the rail top should be preferentially used.In the simulation of the platform fire and the train fire,it is found that the air from the connection port of the platform will form a lateral wind.It has a split control effect on the smoke.The wind speed of the smoke is completely blocked is defined as the critical wind speed.This paper simulates the relationship between the critical wind speed and the fire power.It is found that the maximum fire power that can be controlled by the critical wind speed at the connection port of the station is:5MW in the middle of the train,2MW in the left end of the train,and 3MW in the right end of the train.If station is to control 7.5 MW of fire smoke,the critical wind speed should be 3.4 m/s.