PyroSim-based Simulation Of Smoke Spread From A Multi-storey Underground Transport Hub Fire

With the over-exploitation of urban above-ground space,multi-storey underground transportation hubs have become an inevitable trend in the development of modern urban transportation construction.Its complex structure,special functions and constant updates require higher requirements for the fire and smoke protection of the building,which urgently needs the guidance of relevant theoretical studies.In this paper,we take the space type of multi-story underground transportation hub as a perspective and use numerical simulation to analyze different typical spaces and combined spaces one by one,so as to grasp the smoke spread law of different spaces and formulate targeted smoke control measures to improve the disaster prevention performance of the building.The following conclusions are obtained in this paper.(1)Multi-story underground transportation hub can optimize the opening mode of smoke exhaust valve,using point-action control mode,can improve the efficiency of smoke exhaust and prevent the spread of smoke to other spaces.When designing smoke control in multi-story underground transportation hubs,the smoke control effect is better with multi-point mechanical pressurized air supply than with direct mechanical pressurized air supply,so that the smoke in the space meets the criteria for evacuation to a greater extent.(2)When designing mechanical smoke exhaust for multi-story underground transportation hubs,the orientation of the smoke vent should first be selected as a lateral arrangement.Compared with a downward facing arrangement,the lateral arrangement can contact the smoke in the early stage of the fire to expel it outside,further ensuring the safety of personnel evacuation.Mechanical smoke exhaust combined with make-up air system can avoid excessive negative pressure in the smoke exhaust area,prevent the smoke from being discharged with difficulty,and improve the smoke exhaust efficiency.(3)The interchange hall of multi-storey underground transportation hub has a strong smoke storage and smoke nabbing capacity,which can be used as an independent fire partition to stop the spread of smoke to other spaces.In the early stage of fire,the smoke barrier of a certain height can effectively slow down the spread of smoke to other spaces,but this effect will gradually disappear with the accumulation of smoke;and the combination of air curtain can well make up for the shortcomings of the smoke barrier,and does not affect the normal passage of people.