Research On The Control Of Fire Smoke In The Evacuation Passage On The Top Floor Of The Atrium By Mechanical Air Supply Airflow Organization

With the rapid development of the modern construction industry,multi-functional comprehensive atrium buildings have emerged.At the same time,catastrophic building fire accidents occur frequently,posing a huge threat to people's lives and property.There is no separation between the atrium space and the surrounding floors,and the fire compartment is destroyed by the large space that penetrates from top to bottom.In the event of a fire,high temperature and toxic fumes will quickly diffuse and fill the entire atrium,causing great harm to the lives of personnel.According to the flow characteristics of the fire smoke in the atrium,this article proposes to use the makeup air flow to create an air flow passage that is conducive to the evacuation of personnel on the basis of achieving a balanced exhaust pressure on the basis of previous studies.The top floor of the atrium is the area where smoke first reaches and fills up.Therefore,this thesis adopts large eddy simulation to study the control method of air supplement and smoke exhaust in the evacuation passage of the top corridor when a fire breaks out in the center of the bottom of the atrium.This thesis puts forward a mixed air supplement and smoke exhaust scheme with"breathing area air supplement+upward air supplement",discusses the layout of air inlet,the distribution proportion of air supplement volume,the control effect of air supplement volume on smoke,and the determination of air supplement volume under different heat release rate of fire source.The main research conclusions are as follows:(1)When 6 air inlets with dimensions of width×height:0.667m×1m are arranged in the horizontal direction,and the distance between the air inlets is 2.4m,the smoke control effect is better;(2)When the heat release rate of fire source is 4MW,when the distribution ratio of horizontal side(breathing zone)to vertical make-up air volume is 4:1,the effect of flue gas control is better;when the heat release rate of fire source is 4MW,the optimal air supply volume in the unilateral evacuation passageway for safe evacuation of people in the fire is 20m~3/s,of which the breathing zone make-up air volume is 16 m~3/s,and the vertical upward make-up air volume is 4 m~3/s.(3)When the heat release rate of fire source is 6MW,8MW,and 10MW,the minimum make-up air volume to meet the requirements for safe evacuation of personnel is 28 m~3/s,35m~3/s,40 m~3/s;the make-up air volume increases with the increase of the heat release rate of the fire source,and there is a nonlinear function relationship between the make-up air volume and the heat release rate of the fire source that the slope of the curve decreases.The research results of this thesis are expected to provide a theoretical basis for the design of air supplement and smoke exhaust system in large space buildings such as atriums.