【作者】 彭伟；

【导师】 霍然；

【作者基本信息】 中国科学技术大学 ， 安全技术及工程， 2008， 博士

【摘要】 隧道在给人们带来便利交通的同时,也给火灾防治带来了许多新问题。与一般建筑相比,由于外界环境和隧道自身结构的原因,隧道内始终存在纵向风,当防排烟设备开启后,这种作用更加明显。因此,研究纵向风作用下的隧道火灾特性具有重要意义。本文通过燃烧风洞等小尺寸实验、高速公路隧道全尺寸实验以及FDS数值模拟,研究了纵向风作用下隧道内池火的燃烧速率、隧道拱顶的温度场特性及对火灾探测的影响,射流风机作用下的隧道流场特性,以及典型主辅双洞隧道的排烟控制策略,主要工作包括:在燃烧风洞内开展了不同纵向风速下油池火燃烧特性的小尺寸试验,定量揭示了纵向风对汽油池火燃烧速率的加速效应。油池火是最常见的火灾燃烧形式,其燃烧速率不仅能表示油池火燃烧的快慢,同时也是对火焰高度、火焰温度以及对火焰对周围的热辐射分布等起决定作用的参数。在隧道内纵向风的作用下,油池火的燃烧速率会受到较大的影响。试验中通过改变纵向风速、油池火尺寸、油池火燃料种类,测量了不同水平风速下各种尺寸油池火的燃烧速率;结果表明,在一定的纵向风范围内,随风速的增大,工业酒精池火的燃烧速率先降低后增大,而汽油池火的燃烧速率则随风速线性单调增大,同时发现,方形汽油池火燃烧速率随风速的增长速率与其边长呈幂指数关系。目前的研究结果表明,Hitoshi Kurioka等人由小尺寸试验得出的隧道顶部最高温度预测模型可以用于真实隧道之中。然而,此模型仅能预测纵向风作用下的拱顶最高温度值,对火灾发展初期拱顶温度的变化规律无法预测。本文通过对小尺寸模拟试验和全尺寸试验中火源上方拱顶区域温度数据的分析,得出了其温升速率与无量纲数Fr以及无量纲火源功率Q~*成幂函数关系的结论。另外,还将全尺寸试验中测得的火源上方拱顶区温度数据用于隧道火灾感温探测器报警阈值的设定建议之中。综合考虑了横洞效应,揭示了隧道射流作用下的隧道内气流特征。射流风机是隧道内最常见的烟气控制设备,按照现行的消防控制方式,只要发生隧道火灾,射流风机就应立即启动。本文通过数值模拟的方法研究了射流风机启动后风机附近的流场,以及对火源附近烟气层稳定性和相邻隧道流场等的影响。随后结合数值模拟的结果,提出了隧道火灾发生时不应该开启离火源较近的射流风机,也不应该在火灾初期开启火源下游的射流风机排烟,以免破坏隧道内火灾烟气层的稳定性,影响隧道内人员的安全疏散;另外,对于通过横洞相连的双洞隧道,在排烟时要合理利用横洞,不要因横洞而在排烟时发生“短路”。很多公路隧道具有主辅双洞,辅洞一般情况下被设计为紧急情况时车辆和人员的逃生通道,如何保证人员在疏散过程中的安全显得尤为重要。本文最后结合某多横洞主辅双洞隧道的实际情况,提出了在辅洞内利用射流风机进行正压送风,阻止隧道烟气进入辅洞,保障隧道内人员经辅洞安全疏散的策略。更多还原

【Abstract】 With the convenient transportation to us, tunnels brings many new problem about fire preventation. Compares with the general buildings, due to the tunnel’s own structure characters, there is always longitudinal wind in the tunnel. When the exhaust equipments start, the longitudinal wind becomes stronger. Therefore, study the tunnel fire character under longitudinal wind is very important. The research in this dissertation includes the following aspects:The relation between the burning rate of pool fire and the wind speed in tunnels. Pool fire is the most common style of fire. Its burning rate can not only express how fast the pool fire burns, but also determine some other character such as flame height, temperature of flame, and the distribution of heat radiation around the pool fire. The longitudinal wind has major impact on the burning rate of pool fire in tunnels, however few relevant research was about it. This dissertation gives the burning rate of pool fire in tunnels under different longitudinal wind speed, which was developed through a series of experiments in the combustion-wind-tunnel.The character of temperature field near the vault of tunnel above the fire source. A part of tunnel vault may be in fire plume when a fire occures, its mechanical performance will have big change under the high temperature, even structural destruction can take place. Therefore the study on the character of temperature field near the vault of tunnel above the fire source is particularly important. The present research indicated that, the tunnel vault’s maximum temperature forecast model which obtains by Hitoshi Kurioka et al under scale experiment is able to use in the real tunnel. However, the model can only forecast the vault’s maximum temperature , which can’t forecast temperature rising pattern in the fire growth period. This dissertation gives the maximum temperature rising rate near the vault of tunnel above the fire source, and some suggestion were proposed about the settings of line-type heat detector in tunnels.Behavior of the flow field under the jetfan in tunnels. Jetfan is the most common smoke control equipment in the tunnel. Accoding to the present fire prevention control mode, as long as the tunnel fire occurs, the jetfan system should start immediately. This dissertation studied the flow field near the jetfan after it started with the numerical simulation method, as well as the effect to the stability of smoke layer near the fire source and nearby tunnel. Finally, according to the numerical simulation results, some proposals about the operation of jetfan in tunnel fires were put forward. Smoke control in road tunnel with service tunnel. Many road tunnels have service tunnel, and the service tunnel is designed to be a evacuation passage for vehicles and people in emergency. Therefore, how to assure the safety of evacuees is very important. The dissertation studied two fire control scheme, a suitable one was proposed for this road tunnel in case of fire. Finally, an evacuation method for both people and vehicles is planned based on the principle which let the people and vehicles evacuate separately.更多还原