大型体育场馆火灾应急疏散模拟研究

发布时间：2018-04-02 23:22

本文选题：体育馆　切入点：火灾烟气　出处：《天津理工大学》2017年硕士论文

【摘要】：随着我国社会和经济的高速发展,一些形式新颖、功能齐全的高大净空建筑层出不穷,如体育馆、会展中心等。高大净空建筑火灾烟气蔓延不受限、易产生有毒有害气体、人员密集、疏散距离长、安全疏散难度大以及灭火和救援困难等特点,如果发生火灾,容易造成群死群伤的重特大火灾事故的发生。因此,研究高大净空建筑火灾烟气蔓延时空分布和人员安全疏散过程具有一定的理论和实际应用价值。本文选取某体育场馆为研究对象,采用数值模拟的方法,分析发生火灾时烟气时空分布及人员安全疏散过程,主要工作及结论如下:(1)本文基于火灾动态模拟软件FDS,建立某体育馆三维全尺寸模型,研究发现高温热烟气受到建筑物内气体温度梯度和密度梯度产生的浮力效应垂直上升,产生顶棚射流现象,由于墙壁的阻挡,烟气开始向下运动,在馆内上空形成热烟气层,随着火势发展,烟气层的浓度和厚度逐渐增加,最后布满整个空间;当火源位置在建筑物内不对称时,烟气在大空间内流动的距离延长,其温度和浓度都大大降低,使得烟气层在远离火源位置上空聚集,造成热烟气层不均匀分布。(2)基于火灾烟气蔓延时空分布,依据各出口处烟气层高度和距离地面垂直高度2m高度处温度、CO浓度和能见度危险值确定人员可用安全疏散时间(ASET),火源位于体育馆中央地板时,三个出口的ASET基本相同;火源位于看台座椅时,由于火源位置的不对称性,距离火源最近的出口1的ASET最大,出口3次之,出口2最小;能见度到达危险值的时间最短;启用机械排烟,ASET延长约350s。(3)火灾场景中人员可用安全疏散时间(ASET)和人员所需安全疏散时间(RSET)是判断建筑内人员能否安全疏散的关键。基于Pathfinder对人员疏散的影响因素进行了讨论,确定RSET,火源位于体育馆中央地板时,1068.11s馆内所有人员全部安全疏散到安全区域;火源位于体育馆看台座椅时,由于火源位置的不对称性,火源位置附近的人员优先进行疏散,1106.96s馆内所有人员全部安全疏散到安全区域。通过对比ASET和RSET,发现在机械排烟设施停用时,RSETASET,即全部比赛人员和观众在建筑物内烟气层高度、温度、CO浓度和能见度达到危险值前不能安全撤离;启用机械排烟,ASETRSET,即全部比赛人员和观众均可以在建筑物内烟气层高度、温度、CO浓度和能见度达到危险值前安全撤离。
[Abstract]:With the rapid development of society and economy in our country, there are many tall and empty buildings, such as gymnasium, convention and exhibition center, which have new forms and complete functions.Fire smoke spread is not limited in tall clear space building, it is easy to produce toxic and harmful gas, people are dense, evacuation distance is long, safety evacuation is difficult and it is difficult to extinguish fire and rescue, etc., if a fire occurs,The occurrence of a serious fire accident which is liable to cause mass death and injury.Therefore, it is of great theoretical and practical value to study the spatial and temporal distribution of fire smoke spread and the safety evacuation process of fire in large clearance buildings.In this paper, a gymnasium is selected as the object of study, and the method of numerical simulation is used to analyze the time and space distribution of smoke and the process of safe evacuation in case of fire.The main work and conclusions are as follows: (1) based on the fire dynamic simulation software FDS, a 3D full-scale model of a gymnasium is established in this paper. It is found that the buoyancy effect caused by the temperature gradient and density gradient of the gas in the building increases vertically.Because of the wall blocking the smoke began to move downward and formed a hot flue gas layer over the museum. With the development of the fire the concentration and thickness of the smoke layer gradually increased and finally the whole space was covered.When the location of the fire source is asymmetric in the building, the distance of smoke flowing in the large space is prolonged, and the temperature and concentration of the smoke layer are greatly reduced, which makes the smoke layer gather in the sky away from the fire source.Resulting in uneven distribution of hot flue gas layers. 2) based on the temporal and spatial distribution of fire smoke spread,According to the smoke layer height at each exit and the temperature CO concentration and visibility hazard value at 2 m from the ground vertical height, the safe evacuation time is determined. When the fire source is located on the central floor of the gymnasium, the ASET of the three exits is basically the same;When the fire source is in the stands seat, because of the asymmetry of the fire source position, the ASET of the nearest exit 1 is the largest, the exit 3 is the second, the exit 2 is the smallest, the time of the visibility reaching the dangerous value is the shortest.In the fire scene, the safety evacuation time and the safety evacuation time needed by the personnel are the key to judge the safety evacuation of the occupants in the building.Based on the discussion of the influencing factors of evacuation based on Pathfinder, it is determined that when the fire source is located on the central floor of the gymnasium, all personnel in the museum are safely evacuated to the safe area, and the fire source is located in the stadium stands seat.Due to the asymmetry of the location of the fire source, the personnel near the fire source priority to be evacuated to the safe area in 1106.96s.By comparing ASET and RSET, it is found that RSETASET can not be safely evacuated when the mechanical smoke exhausting facility is stopped, that is, all the race personnel and spectators are unable to evacuate safely before the height of the flue gas layer, the concentration of CO and the visibility reach the dangerous value in the building.Use of mechanical smoke exhaust, ASETRSET, in which all racing staff and spectators can safely evacuate before the height of the building's flue gas layer, temperature, CO concentration and visibility reach a dangerous value.
【学位授予单位】：天津理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU998.1

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