细水雾和排烟共同作用下公路隧道火灾下沉式疏散研究

发布时间：2018-04-12 20:09

本文选题：公路隧道 + 火灾　；参考：《沈阳建筑大学》2015年硕士论文

【摘要】：现今,公路隧道已成为城市主要交通枢纽之一。随着城市化进程的快速推进,交通公路隧道与日俱增,随之而来的安全问题也一直受到各方的关注。当公路隧道发生火灾时,有效地控制火灾发展及烟气蔓延,为人员疏散争取充足的时间,创造最有利的逃生环境成为研究的重要课题。细水雾灭火系统具环保、高效、节水和电绝缘性好等优势,但细水雾作用会压低烟气,增加烟气层厚度。笔者将细水雾和机械排烟共同作用,对公路隧道火灾情况下烟气和火势的控制进行研究,同时对下沉式纵向疏散逃生楼梯间距进行优化分析。本文首先利用FDS+Evac软件建立1000m长的公路隧道18MW火灾模型,在不采用细水雾和排烟等措施的情况下进行不同逃生楼梯间距下的人员疏散模拟,分别比较了逃生楼梯间距为60m、80m、100m、120m、140m和160m时公路隧道火灾温度场发展、烟气蔓延情况、能见度、各逃生楼梯的使用时间及实际所需总逃生时间等性能参数。综合分析在没有消防措施的情况下,1000m单向单车道公路隧道下沉式纵向疏散最优化的逃生楼梯间距不宜超过100m。其次,笔者着重分析机械排烟作用对公路隧道火灾烟气的控制。本文采用集中排烟方式,通过比较不同工况的集中排烟对火灾温度场、烟气纵向覆盖范围、CO浓度和能见度变化等火灾态势蔓延的控制作用,发现集中排烟方式对火灾烟气具有较好的控制效果,而且在研究的集中排烟工况中,排烟口风速8m/s,排烟口面积8m2,排烟口个数为8个时的控烟效果最优。再次,研究细水雾系统对公路隧道火灾的控制效果。将25m隧道定为一个细水雾保护分区,分别研究作用范围为2个、3个和4个保护分区时细水雾对公路隧道火灾的控制效果,对比三种工况下温度发展、烟气蔓延及能见度等方面,结果表明作用范围为3个保护分区(75m)工况是细水雾控制火灾的最优方案。最后,研究了细水雾系统和集中排烟系统共同作用时的最优方案及在此工况下逃生楼梯间距的二次优化。通过比较不同细水雾和机械排烟工况对火灾的控制效果,发现细水雾作用范围为3个保护分区(75m),流量10L/min,机械排烟使用8个排烟风口,每个风口面积8m2,风速8m/s的工况为最优方案。在此工况下对逃生楼梯间距进行二次优化,当逃生楼梯间距为120m时,火灾人员疏散所需总时间为355s,各逃生楼梯的拥堵情况不是很严重,4号逃生楼梯的人员在可利用安全疏散时间内完成疏散；当逃生楼梯间距为140m时,3号和4号逃生楼梯处发生严重的人员拥堵现象,拥堵时间较长,而且疏散总时间超多360s,不符合要求。因此,笔者认为在有机械排烟和细水雾措施的情况下,逃生楼梯间距可以设为120m。
[Abstract]:Nowadays, highway tunnel has become one of the main traffic hubs in the city.With the rapid development of urbanization, traffic highway tunnels are increasing day by day.When highway tunnel fire occurs, it becomes an important research topic to control the fire development and smoke spread effectively, to buy sufficient time for evacuation and to create the most favorable escape environment.The water mist fire extinguishing system has the advantages of environmental protection, high efficiency, water saving and good electrical insulation, but the fine water mist will lower the smoke and increase the thickness of the flue gas layer.The author studies the control of smoke and fire intensity in highway tunnel fire by the combined action of water mist and mechanical smoke exhaust. At the same time, it optimizes the staircase spacing of sinking longitudinal evacuation escape.In this paper, a 1000m long 18MW fire model of highway tunnel is established by using FDS Evac software. The evacuation simulation of different escape staircase spacing is carried out without water mist and smoke exhaust.The performance parameters of highway tunnel fire temperature field development, smoke spread, visibility, service time of each escape staircase and the actual total escape time are compared when the escape staircase spacing is 60m / 80m / 100m / 100m and 160m respectively.A comprehensive analysis is made on the optimization of escape staircase spacing of 1000m one-way single-lane highway tunnel under sinking longitudinal evacuation without fire protection measures should not exceed 100m.Secondly, the author focuses on the analysis of mechanical smoke emission on highway tunnel fire smoke control.In this paper, the effects of centralized exhaust smoke under different working conditions on fire temperature field, smoke longitudinal coverage range, CO concentration and visibility are compared in this paper.It is found that the centralized exhaust smoke has a better control effect on the fire smoke, and the best smoke control effect is when the wind speed of the flue gas outlet is 8 m / s, the area of the outlet is 8 m ~ 2 and the number of the exhaust port is 8 m ~ 2.Thirdly, the control effect of water mist system on highway tunnel fire is studied.The 25m tunnel is designated as a water mist protection zone. The effect of water mist on the fire control of highway tunnel is studied in 2, 3 and 4 protection zones, and the temperature development, smoke spread and visibility are compared under three conditions.The results show that the optimal scheme of water mist fire control is that the range of action is 3 protection zonings (75 m).Finally, the optimal scheme of water mist system and centralized smoke exhaust system and the secondary optimization of escape staircase spacing under this condition are studied.By comparing the fire control effects of different water mist and mechanical smoke exhausting conditions, it is found that the action range of water mist is 3 protection zones (75 m / min), flow rate (10 L / min), 8 exhaust vents with an area of 8 m ~ 2 for mechanical exhaust smoke, and the optimal scheme is the working condition of wind speed 8m/s.Under this condition, the distance of escape staircase is optimized twice. When the distance of escape staircase is 120m,The total evacuation time of fire personnel is 355s, the congestion of each escape staircase is not very serious, the personnel of the No. 4 escape staircase can use the safe evacuation time to complete the evacuation;When the distance of escape staircase is 140m, serious people congestion occurs in the three and four escape staircases, the congestion time is longer, and the total evacuation time is more than 360 s, which does not meet the requirements.Therefore, the author thinks that the distance of escape staircase can be set to 120 m under the condition of mechanical smoke exhaust and fine water mist.
【学位授予单位】：沈阳建筑大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U458

【相似文献】