Numerical Simulation And Field Test Of Smoke Control System In Public Area Of Urban Subwav Atrium Station

Atrium is a new design form for the public area of metro station.It can enhance the integrity and openness of the station internal environment.At the same time,the smoke ventilation in the station faces new challenges due to the more spacious space.This paper is aiming at the structural characteristics of the public area of atrium metro station.Firstly,theoretical analysis was used to design and check the smoke control system of the station.Then,based on Fire Dynamics Simulator(FDS),the smoke movement law of station platform and hall were studied using large eddy simulation technology,and the influence of the smoke exhaust fan was analyzed.At last,hot smoke tests was used to further verify the effect of smoke ventilation,and the smoke control system of the station has been optimized.The main conclusions obtained are as follows:(1)Taking the public area of Wujiang road station of Hangzhou metro line 1 as an example,the atrium was closed as a separated smoke-free zone by installing rolling curtain wall under the roof of upper structure in atrium.At the same time,the exhaust duct made of fire-proof glass was set between the escalator and stair.The theoretical calculation showed that under the design,the wind speeds of each stair and escalator could meet the wind speed requirement of 1.5 m/s in Subway Design Standard(GB 50157-2013).(2)The numerical simulation of fire in the central part of the platform showed that when the exhaust fan was not turned on,the smoke blocking wall played a certain role in blocking smoke.But due to the rapid diffusion of flue gas,and the air velocity in most areas of the stairs cannot meet the standard requirements,it was not beneficial to the escape and evacuation of personnel.When the exhaust fans in public areas and TVF fans at both ends of the station were turned on,exhaust fans assisted the smoke exhausting.When the air-conditioning system was turned on,the effect of the atrium smoke exhaust duct was obvious,while the smoke exhaust on both sides of the platform exhaust effect was not.The area from the lower edge of the escalator to the section directly below the smoke blocking wall,the speed can meet the requirements of the standard,and the direction of which was opposite to that of personnel escape.The height of the smoke layer within 300s was above the respiration level of the personnel to insure people can be safely evacuated.(3)The numerical simulation of the hall fire showed that when the smoke exhaust fan was not started,the smoke blocking wall also played a certain role in blocking smoke.The flue gas was mainly diffused in the whole station hall and platform was relatively safe.2 minutes after the fire occurred,the height of the flue gas in the station closed to the equipment room on the fire source side,began to drop below the respiration level of the personnel.But the other side against the fire source was relatively safe,which can meet the safety evacuation requirements.When the exhaust fans of the station hall were started,the wind filling from the station entrance,and the smoke exhaust effect was not obvious at this time.2.5 minutes after the fire,the height of flue gas in the station closed to the equipment room on the fire source side began to drop below the breathing height.While the diffusion speed of the other side of hall was slow,the distributions of station temperature and smoke were beneficial to the evacuation of personnel.And the rate of air flow could meet the standard requirements.(4)The hot smoke test of station platform and hall showed that the startup of the TVF fan,exhaust fan and exhaust fan could make the smoke layer be concentrated in the upper part of the space where the fire was located.And the height of the human body was basically insensitive to the hot smoke.Targeting the atrium fire,when the roller smoke blocking wall was fall down,the stair and escalator showed a larger downward flow.In addition,fire-proof glass should be added to the side of the stair and escalator.After additional fire-proof glass has been added,the wind speed of the large and small staircase escalator stairways was further increased,and the wind speed would meet the requirements of the standard.