Research On Fire Smoke Flow Simulation And Control In Subway Platform

Subway is one of the most important traffic tools in the city's future public transport.Because of its own design,it has many advantages,such as large passenger volume,fast speed,low energy consumption,convenient and comfortable and so on.It is widely concerned by all countries in the world.But there are new problems such as the complexity and uncertainty of the structure itself.Once a fire occurs,it will cause serious consequences.In many dangerous factors,the smoke produced by the fire is the main cause of the casualties.In the case of fire,if the smoke can not be eliminated in time,the smoke will spread to the staircase.Moving to the station hall,and the staircase is the main access to evacuate,which will bring great difficulties to evacuation and safety relief.It is of great significance for the prevention and control of subway fire to study the rules of fire flue gas flow and take corresponding prevention and control measures.This paper analyzes the fire cases of subway stations in the past years,and then combines the theory of fire smoke theory and the working principle of wind exhaust system,taking a double deck subway in Nanjing as the research object,setting up the geometric and physical model,setting the corresponding parameters and using the FDS fire simulation software for numerical simulation.The main contents of the study are the location of different fire sources,the power of different fire sources,the wind speed and the influence of the air curtain on the spread of the fire smoke flow.By observing the parameters of the smoke,we can judge whether the people can evacuate safely during the fire,and the analysis object includes the smoke distribution,the smoke temperature,the visibility of the CO concentration meter and so on.The best flue gas control mode is selected to provide theoretical basis for fire prevention and control of subway fire.According to the comparison and analysis of different working conditions,the power of the fire source increases and the other conditions are constant,the smoke spread also increases,which is not conducive to the evacuation of the personnel,and the increase of the exhaustwind speed,and the other invariable,can effectively reduce the spread of the flue gas;the location of different fire sources also affects the flow of smoke,and the location of the fire source occurs at the platform.When it's in the middle,smoke will spread to both sides of the staircase to the station hall,which is not conducive to evacuation.Through the analysis and summary,in the natural exhaust air,the flue gas can be eliminated in time.When the exhaust wind speed and the supplemental wind speed are 10m/s and 2.5m/s respectively,the effect of exhaust smoke is the best.When the air curtain is used,the air curtain wind speed is 5m/s is the best control effect on the flue gas flow.The exhaust system and air curtain open simultaneously have obvious effect on smoke control.