地铁区间隧道火灾烟气流动规律及控制方法研究

发布时间：2018-04-15 22:36

本文选题：地铁区间隧道 + 烟气蔓延　；参考：《中国矿业大学》2017年硕士论文

【摘要】：随着我国经济与社会的快速发展,我国道路建设呈现出一派繁荣的景象,越来越多的地铁隧道出现在城市中。火灾是地铁隧道在使用过程中需要重要关切的问题。由于地铁隧道深埋于地下,一旦在区间隧道发生火灾时,产生的有毒烟气与热量不断积聚,会严重的影响人员安全和隧道的结构安全,因此开展相关的隧道烟气蔓延规律与防控研究是隧道安全的必要研究课题。近些年来,许多的专家学者针对隧道火灾烟气蔓延与火灾下隧道结构稳定性开展了相关的研究,本文针对目前研究的现状以及存在的不足,进行了以下几个方面的研究。本文通过相似性准则建立了缩尺寸地铁区间隧道模型并在此基础上进行火灾试验,通过开展不同功率下的实验获得了隧道内的纵向温度数据以及烟气层数据,通过对数据的处理并着重分析了不同火源功率下拱顶纵向温度分布,发现纵向烟气最大温升大致呈幂指数衰减,且在距火源一定距离处基本不再减少。为了验证火灾模拟软件对于开展隧道火灾实验模拟的可行性,利用FDS建立了与实验情况相同的工况,并对实验模型进行1:1建模,分别对隧道拱顶最高温度、烟气层稳定厚度、拱顶纵向温度分布进行了对比分析。结果表明,设置合理的模拟参数,模拟与模型实验所得到的数据基本一致,利用FDS进行隧道火灾相关方面的研究具有一定的科学性与可行性。并通过结合模拟获得的纵向顶棚最高温度分布的模型与实验获得结果,得出了烟气层顶部的最高温升与Q*2/3/Hf5/3的关系式。结合工程实际,通过FDS建立不同火源功率与纵向风速条件的火灾模型并进行模拟研究,获得了自然通风状态下的烟气蔓延以及烟气温度分布情况;通过设置隧道内的不同的纵向通风的风速值,并对结果进行分析获得了隧道内纵向风速值与烟气回流的回流长度的关系,临界风速与无量纲热释放速率的关系式,并最终获得了回流发生的临界风速值。本文利用理论分析、相似性准则实验与FDS模拟研究的方法,并结合相关的工程实际对地铁区间隧道内的火灾产生的烟气蔓延规律及其控制方法进行了研究,重点分析了烟气层顶部纵向温度分布与纵向风速对烟气蔓延相关参数的影响。本文的研究成果可以为地铁隧道区间火灾的烟气控制与人员安全研究的提供一定的理论基础。
[Abstract]:With the rapid development of our country's economy and society, the road construction of our country presents a prosperous scene, more and more subway tunnels appear in the city.Fire is an important concern in subway tunnel operation.Because the subway tunnel is buried deep underground, once the fire occurs in the tunnel, the toxic smoke and heat produced will accumulate continuously, which will seriously affect the safety of the personnel and the structural safety of the tunnel.Therefore, it is necessary to carry out the research of tunnel smoke spread law and prevention and control.In recent years, many experts and scholars have carried out related research on tunnel fire smoke spread and tunnel structure stability under fire.Based on the similarity criterion, the tunnel model of the reduced size subway section is established and the fire test is carried out. The longitudinal temperature data and smoke layer data are obtained by the experiments under different power levels.By processing the data and analyzing the longitudinal temperature distribution of the dome under different fire source power, it is found that the maximum temperature rise of the longitudinal flue gas tends to decay exponentially and does not decrease basically at a certain distance from the fire source.In order to verify the feasibility of the fire simulation software for the tunnel fire simulation, the operating condition of the tunnel fire simulation software is established under the same condition as the experiment by using FDS, and the experimental model is modeled at 1:1. The maximum temperature of the tunnel vault and the stable thickness of the flue gas layer are respectively analyzed.The longitudinal temperature distribution of the vault is compared and analyzed.The results show that with reasonable simulation parameters, the simulation results are basically consistent with those obtained from the model experiments, and it is scientific and feasible to use FDS to study the tunnel fire related aspects.The relationship between the maximum temperature rise at the top of the flue gas layer and Q*2/3/Hf5/3 is obtained by combining the model of the maximum temperature distribution of the longitudinal ceiling and the experimental results obtained by the simulation.Combined with engineering practice, the fire models of different fire source power and longitudinal wind speed were established by FDS and simulated, and the smoke spread and flue gas temperature distribution under natural ventilation were obtained.By setting the wind speed values of different longitudinal ventilation in the tunnel and analyzing the results, the relationship between the longitudinal wind velocity value and the reflux length of flue gas reflux in the tunnel and the relation between the critical wind speed and the dimensionless heat release rate are obtained.Finally, the critical wind speed is obtained.In this paper, the method of theoretical analysis, similarity criterion experiment and FDS simulation are used to study the smoke spread law and control method of fire in subway tunnel.The influence of vertical temperature distribution and vertical wind speed on flue gas spread is analyzed.The research results in this paper can provide a theoretical basis for the smoke control and personnel safety research of subway tunnel fire.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U458.1

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