地铁隧道非单一火源火灾时期排烟效果模拟研究

发布时间：2018-06-14 23:21

本文选题：地铁车站 + 多火源火灾　；参考：《中国矿业大学》2017年硕士论文

【摘要】：近年来地铁发展迅速,在便利市民出行的同时也带来了一系列城市安全问题。地铁易发生洪涝、火灾、坍塌等灾害,其中火灾发生次数最多,危害性最为严重,而有毒烟气是造成人员死亡的主要原因。地铁车站由于人员密集且内部空间相对封闭,易成为恐怖袭击的目标,存在多点起火的隐患。国内外学者曾对地铁火灾时期排烟模式作了大量研究,但主要集中在单点火源火灾场景,鲜有对非单一火源点火灾场景的研究,基于此,本文重点对地铁发生双点火源火灾时期排烟模式展开研究。本文以宁波某车站为研究对象,假设车站两不同地点同时发生火灾,采用FDS火灾模拟软件对站台-站台、站台-轨行区、轨行区-轨行区双点火源火灾场景下排烟模式进行数值模拟研究,本文主要研究了屏蔽门和隧道风机TVF联动排烟对地铁车站火灾烟气控制效果和对乘客安全疏散的影响。为确定出各火灾场景下的最优排烟模式,本文选取了站台温度场、速度场、能见度、CO浓度等能反应排烟效果的一些参数进行分析。模拟结果表明地铁发生站台-站台双点火源火灾时,宜开启火源附近局部屏蔽门和隧道风机TVF,采用“全排式”排烟方法辅助排烟;地铁发生站台-轨行区双点火源火灾时,宜开启火源附近局部屏蔽门并利用隧道风机TVF辅助排烟;地铁发生轨行区-轨行区双点火源火灾时,宜关闭站台非着火侧屏蔽门并开启非着火侧隧道风机TVF与着火侧TVF联动辅助排烟。在最优机械排烟模式下能保证站台层安全高度处温度低于65℃,疏散线路能见度大于10 m、CO浓度低于225 ppm,楼梯口处能形成向下稳定的大于1.5 m/s的风速,最有利于乘客安全疏散。除站台、轨行区火灾外,区间隧道也会因电缆或列车故障引发火灾,本文主要对火灾时期烟气逆流现象进行分析。首先研究了单点火源火灾场景,发现烟气逆流长度与纵向风速成反比关系,烟气逆流长度随纵向风速的增加而减小,且纵向风速越小烟气逆流距离增加的幅度越大;烟气逆流长度随火源功率的增加而增加,但随着火源功率的增加烟气逆流长度增加的幅度逐渐越小,当火源功率大于12.5 MW时,烟气逆流长度随火源功率变化不明显。并利用量纲分析方法,得出烟气逆流长度与火源功率、纵向风速等物理量的并且根据模拟数据,拟合出了单火源烟气逆流长度预测公式。为进一步研究双火源火灾时期烟气逆流规律,本文基于上述单火源烟气逆流长度预测公式的推导过程,对双点火源火灾烟气逆流现象进一步分析。研究发现双火源间距越大,烟气逆流长度越短,无量纲烟气逆流长度d*与距离影响系数β成幂函数关系;双火源功率越大,烟气逆流长度越长,双火源比例系数k与火源功率影响系数α成对数函数关系。引入参数α和β对单火源公式加以修正得到双火源烟气逆流长度预测公式。并且将公式预测值和模拟值进行对比,发现预测公式预测结果较为准确。
[Abstract]:The subway has developed rapidly in recent years, and it has also brought a series of urban safety problems at the same time. The subway is prone to flood, fire, collapse and so on, among which the number of fires and the most dangerous is the most dangerous, and the toxic smoke is the main cause of the death of the people. The subway station is due to the densely staffed and internal space of the subway station. Closed, easily become the target of terrorist attacks, there are many hidden fires. Scholars at home and abroad have done a lot of research on the mode of smoke emission during the subway fire period, but mainly concentrated on the fire scene of single point fire source, and there are few research on fire scene of non single fire source. Based on this, this article focuses on the smoke exhaust mode during the dual fire fire period in the subway. This paper, taking a station in Ningbo as the research object, assumes that there is a fire at the station two at the same time, and uses the FDS fire simulation software to simulate the smoke exhaust mode of the platform - platform, the platform rail line, the rail line area and the rail line double point fire scene. This paper mainly studies the shield door and the tunnel fan TVF Union. The effect of smoke control on the smoke control of subway station fire and the safety evacuation of the passengers. In order to determine the optimal smoke exhaust mode in every fire scene, this paper selects some parameters of the platform temperature field, velocity field, visibility, CO concentration and other parameters that can react to smoke and exhaust smoke. The simulation results show that the subway station platform and platform is double ignition. In the source fire, it is appropriate to open the local shielding door near the fire source and the tunnel fan TVF, and use the "full row" smoke exhaust method to assist the smoke exhaust. When the subway station platform rail line area double point fire source fire, it is appropriate to open the local shielding door near the fire source and use the tunnel fan TVF to assist the exhaust smoke; when the subway line area rail line area double point fire fire fire, it should be closed. The non ignition side shield door and open fire side tunnel fan TVF and the ignition side TVF auxiliary smoke exhaust. Under the optimal mechanical smoke mode, the temperature of the platform layer is lower than 65 C, the visibility of the evacuation line is more than 10 m, the CO concentration is less than 225 ppm, and the staircase can form the wind speed of more than 1.5 m/s at the staircase. It is beneficial to the safe evacuation of passengers. In addition to the platform and the fire in the rail line, the interval tunnel will also cause the fire caused by the cable or train failure. This paper mainly analyzes the phenomenon of the backflow in the fire period. First, we study the fire scene in the single point fire source, and find the inverse relationship between the length of the flue gas countercurrent and the longitudinal wind speed, and the length of the counter flow of the flue gas follows the longitudinal wind speed. The increase is reduced, and the smaller the longitudinal wind speed is, the greater the increase of the backflow distance, the increase of the backflow length of the flue gas increases with the increase of the fire power, but with the increase of the power of the fire, the increase in the length of the counter flow is gradually smaller. When the power of the fire source is greater than 12.5 MW, the reverse flow length of the flue gas is not obvious with the power of the fire source. In order to further study the rule of the smoke countercurrent in the fire period of double fire source, this paper is based on the deduction process of the prediction formula of the smoke counter flow length of the single fire source. It is found that the larger the gap between the two fire sources, the shorter the length of the backflow of the flue gas, the relationship between the length d* of the non dimensional flue gas and the power function of the distance influence coefficient beta, the longer the power of the double fire source, the longer the length of the counter flow of the flue gas, the logarithm function of the ratio of the double fire source ratio and the influence coefficient of the fire power. The formula of the single fire source is corrected by the introduction of parameter alpha and beta, and the prediction formula of the counter current of the double fire source is obtained, and the prediction value of the formula is compared with the simulated value, and the prediction results are more accurate.
【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

【参考文献】