着火地铁列车继续行驶的火灾特性研究

为了研究着火地铁列车在隧道内继续行驶的火灾特性,搭建1∶4的列车与隧道模型,通过改变风机的风速模拟地铁列车在隧道内行驶的不同速度,采用柴油油池火作为火源,分析火灾情况下车厢内温度分布。结果表明:着火列车静止时车厢内温度上升速率最快,温度峰值最大,随着风速增加,车厢内最高温度逐渐降低,但烟气蔓延速度也随之增大;较高的风速会抑制热烟气从车窗流出,导致车厢温度在火灾后期迅速升高,同时使车厢高温区域的范围增大,分析得到着火地铁列车继续行驶的安全速度在7～9 m/s之间;分析并拟合了车厢内上部温度与时间的关系式,发现车厢温度大致以幂指数的规律衰减。     

区间坡度对停驶地铁列车火灾烟气自然扩散的影响

采用三维场模拟与一维网络模拟相耦合的多尺度模拟方法，对列车中部着火且相邻车站风机未启动阶段的烟气自然扩散进行研究。地铁长区间隧道坡度分别为0‰、12‰、21‰、30‰，分析坡度对区间隧道火灾烟气扩散及控制产生的影响。综合分析温度、CO 浓度和能见度等因素，研究了火灾初期隧道环境随时间变化的危险性，确定了人员可利用的安全疏散时间。列车阻塞于区间隧道的坡度区段时，当坡度达到30‰，由于回流现象的出现导致隧道内CO 浓度出现了阶跃性变化。     

地铁区间隧道火灾通风模式的数值分析

介绍了地铁区间隧道火灾常见的几种通风排烟模式,对其中一种最复杂的模式进行了数值分析。模拟分析得出,对于地铁实际工程中的单线盾构圆形隧道,在10 MW火灾强度下,着火区间隧道内2.6~2.9 m/s左右的纵向风速可以有效阻止烟气发生逆流;在着火区间隧道2.9 m/s的纵向风速下,未着火区间隧道两端对送送风速度为1~1.5 m/s时,联络通道内有风速为6 m/s左右的气流流向着火区间隧道,可有效抑制烟气通过联络通道向未着火区间隧道蔓延,保证人员的安全疏散。     

天津地铁地下空间声环境测量研究

通过天津地铁1、2、3号线车站噪声值、列车在区间隧道运行时车厢内部噪声值的测量,从而确定天津地铁的部分车站、区间噪声评价指标并通过对比与分析多种工况下地铁车站噪声、列车在隧道运行时车厢内噪声的变化,进而量化各工况改变时的噪声变化值。经研究明确天津既有线路的噪声水平及其分布规律,可进一步为地铁车站声环境改善措施、新线声环境设计提供优化依据。     

新建地铁隧道内活塞风温度变化理论分析

列车在地铁隧道中运行时,会产生大量的热,一部分被隧道内岩土层吸收,其它部分散失在空气中,随列车活塞风带入站台。本文假设在新建单线隧道,一列车行驶周期内,对隧道内活塞风温度变化规律进行理论分析。隧道内列车散热假设为移动热源,将隧道区间内的空气流动简化成一维管流,活塞风与隧道壁面发生对流换热,根据隧道内空气的热平衡,建立简单的流固耦合模型。简化后得到新建地铁区间隧道活塞风温度变化数学模型,并给出其数值计算方法,借鉴上海某地铁的参数,利用MATLAB软件计算并绘出整个过程中隧道内活塞风温度变化曲线,隧道内活塞风温度下降约1.9 ℃。分析发现隧道内的岩土层温度、隧道长度和列车速度等影响隧道内温度分布和温度变化幅度。     

列车状态对地铁车站轨道排风系统运行工况的影响

通过实时监测广州地区3种不同型式地铁站车站段隧道列车状态及轨底、轨顶排风的风速与温度,考察了列车状态变化对地铁车站轨排系统的影响。结果表明:列车状态的变化会影响车站段隧道的静压,静压为正值时,排风机的排风作用增强,相反,排风机的排风作用减弱;端头连通车站及侧式车站的泄压作用会削弱列车状态对轨排系统的影响;轨排系统具有一定的轨顶排热作用,列车停站时间越长,排热作用越明显;轨底排热作用在3种型式地铁车站中均不明显。     

北京新建地铁通风空调系统模拟分析

本研究以北京新建地铁四号线第三标段隧道和车站为对象,借助SES软件,建立数学模型,对两种典型的通风空调系统方案正常工况运行进行数值模拟。分析得出产热量的分布规律;列车行车状况、活塞风井、不同形式车站及区间隧道通风空调系统对隧道内速度场、温度场及新风量的影响规律。研究同时对通风空调系统方案进行了初步的技术经济比较。本研究为分析地铁通风空调系统的空气流动与传热提供了参考,为新建地铁通风空调系统方案的选择、设计及科学地运行管理提供有价值的数据资料。     

利用地铁区间隧道间联络通道排烟的可行性研究

提出了对着火区间隧道两端送新风、利用地铁区间隧道间的联络通道向相邻区间隧道排烟的方法,利用CFD软件模拟并验证了该方法的可行性,得出了该情况下的最佳送风速度.     

暗挖换乘通道对既有车站和区间影响分析

北京草桥地铁站为既有10号线与新建19号线、新机场线的换乘车站,新建车站与既有车站的换乘通过长距离换乘通道方式实现,换乘通道采用暗挖法施工,且紧邻区间隧道和地铁车站,施工影响较大.提出了双导洞台阶法+施工控制+深孔注浆联合保护措施,依据规范要求提出了相应的位移控制指标,建立了包含换乘通道与既有地铁结构的三维计算模型,分析了车站、隧道的竖向和水平位移的变化规律.结果表明:换乘通道临近区间隧道和地铁车站施工,除施工控制措施外,需要辅助以深孔注浆措施;区间隧道和车站的最大位移值分别为4.04和4.50mm,小于变形控制允许值,地铁结构位移余量足够;最大位移发生在区间隧道与地铁车站连接处和地铁车站端头位置,需在现场监测中重点关注,加密该位置测点;南侧换乘通道施工引起的竖向位移和横向水平位移占位移总量66%以上,是地铁结构安全保护的关键步骤.     

新加坡地铁消防怎么做

新加坡地铁拥有3条干线,每个地铁车站都安有屏蔽门系统。这种屏蔽门系统是安装在地铁站台靠近轨道侧边沿,把站台区域与列车区域互相隔开的设施。它的主要功能是：防止乘客跌落轨道产生意外事故;降低车站空调通风系统的运行能耗;减少列车运行噪音和活塞风压对乘客的影响,同时也是两道防火防烟分隔物。假如列车在隧道内着火,因设有这两道屏蔽门,就可以防止烟雾和毒气进入车站。同样,如果上行线列车在车站失火,也不会殃及下行线列车。按照运行秩序,只要列车尚未进站,屏蔽门总是关闭着的,旅客安全则有充分的保障。     

Prediction of smoke back-layering length under different longitudinal ventilations in the subway tunnel with metro train

Due to the small width and the large train blockage ratio in subway tunnel, the smoke back-layering will be different from that in the wider road tunnel with small vehicle blockage ratio. In the train blockage region of tunnel, the velocity of longitudinal ventilated air-flow interacting with the back-flowed smoke gas is different from that in the upstream tunnel without train blockage. Then the back-flowed smoke gas might be prevented in the train blockage region with higher ventilation velocity, otherwise it would be stopped in the upstream tunnel without train blockage but with lower ventilation velocity. They were taken into consideration separately and an equivalent fire source was introduced by dividing the dimensionless heat release rate of fire source into two parts in the cases where the smoke back-layering length is longer than metro train length. A series of full-scale numerical simulations are carried out with FDS to investigate the smoke back-layering length in subway tunnel with different train lengths and longitudinal ventilation velocities. The simulation results indicate that the influence of metro train length on the smoke back-layering is great and cannot be ignored any more. A global correlation model is proposed based on the dimensionless analysis and simulation results.     

公铁合建越江隧道列车运动压力波数值模拟

本文采用CFD方法对地铁通过公铁合建越江隧道产生的压力波进行了数值模拟分析。基于国内某公铁合建越江隧道相关尺寸建立其下部地铁隧道三维几何模型,采用动网格方法模拟列车从驶入到驶出隧道的全过程。利用国外模型实验数据验证了本文数值模拟方法的可靠性,根据隧道内压力变化曲线,分析了由于列车通过隧道引起的压力变化规律。计算得到进入疏散通道防火门处的压力峰值,最大值1910Pa,最小值-1060Pa,与疏散通道内30~50Pa的正压有较大的压力差。     

Optimization of emergency ventilation mode for a train on fire stopping beside platform of a metro station

This paper presents a computational fluid dynamics (CFD) simulation investigation of most effective cooperative operation mode of the tunnel rail track area exhaust system and the platform ventilation system for the emergency scenario of a train on fire stopping beside the platform of a subway station. CFD simulations are carried out by fire dynamics simulator (FDS) to analyse and compare the computed field distributions of smoke temperature and visibility, as to find out the most optimal cooperation mode of these ventilation systems. Results show that only starting the over track exhaust (OTE) system can control the smoke more effectively than starting both the OTE system and the under platform exhaust (UPE) system at the same time. In addition, setting the platform ventilation system as exhaust pattern can provide better control performance than setting it as air supply pattern, in counteracting the smoke flowed into the platform from the fire train. Therefore, it is found out and suggested that in such an emergency condition, the most effective strategic cooperative ventilation mode is only starting the OTE system of the tunnel rail track area with the aid of activation the smoke exhaust pattern of the platform ventilation system.     

Smoke Movement in a Sloping Subway Tunnel Under Longitudinal Ventilation with Blockage

Critical velocity and smoke back-layering length are two of the determining parameters to the fire risk assessment of subway tunnel. These two parameters of a sloping subway tunnel with train blockage were investigated both experimentally and numerically in this paper. To address the influences of slope, the slopes of 0, 3, 6, 9, 12, 15% in downhill subway tunnel were studied and the height (H) of the tunnel was replaced by the inclined tunnel height (\( H/\cos \theta \)). The train model with a dimension of 2 m (length) × 0.3 m (width) × 0.38 m (height) was also chosen in simulations and experiments for the tunnel blockage. Thenceforward, 30 reduced-scale experimental and 150 numerical scenarios were analyzed to predict the critical velocity and smoke back-layering length in various sloping subway tunnels. Six different heat release rates including 5.58, 11.17, 16.67, 22.35, 27.94, and 33.52 kW were considered in the experiments and five different heat release rates including 2.79, 5.58, 8.38, 11.17 and 16.67 kW were considered in the simulations. Based on the comparison in the horizontal tunnel, numerical results were quite consistent with the experiments. The results showed that train blockage influenced the smoke back-layering length, and the critical velocity increases with the tunnel slope. Finally, empirical models were developed to predict the critical velocity and smoke back-layering length in a sloping subway tunnel with train blockage.     

Safe velocity of on-fire train running in the tunnel

The safety of a running train on fire in a tunnel is a key issue for rescue operations, and the train velocity is mainly related to its safety. In this study, the relationship between the wind velocity and heat release rate (HRR), temperature field around the train, and flame/smoke pervasion rule were investigated under the conditions of variable train velocity, fire location, and fire source location. Beijing Metro was considered as a typical example, in which the safe velocity was estimated to be ∼41.83 km h⁻¹. Assuming the occurrence of fire at the center of the train, the numerical simulations of the flow field using the sliding grid of CFD were performed for a full-scale tunnel under different HRRs. When the fire source reached to the target section, the velocities of all the monitoring points rapidly increased. The velocities increased as the train tail arrived at the target section. The velocities at the measuring points increased with the increase in height, excluding the value of the position with a distance of 0.025 m from the tunnel ceiling. The average temperature and concentration of smoke in the annular space between the train and tunnel ceiling had the minimum values when the running train on fire moved with a speed of 45 km h⁻¹. Thus, the safe velocity of a subway train on fire should be managed between 41.83 km h⁻¹ and 45 km h⁻¹.     

地铁列车火灾停靠站台与隧道的处置利弊

对列车所处位置在扑救火灾时的影响进行利弊分析，证明地铁列车发生火灾时，停在站台处置比停在隧道内处置具有人员疏散逃生方便、排烟效果好、救援人员行动便捷、灭火战斗行动快速等明显优势。在处置地铁列车火灾中排烟和救人是最重要的措施，应根据燃烧部位和列车停靠位置的不同，正确选择送排烟方向，及时组织人员疏散。     

上海市域高速铁路隧道火灾疏散研究

上海市域高速铁路为城际列车和地铁列车共线运行的运营模式,通过数值模拟得到不同通风方式、火源位置、疏散口间距下的人员可用安全疏散时间和必需安全疏散时间,分析人员疏散安全性,为安全疏散设施设置方案提供决策依据。结果表明：地铁列车火灾比城际列车火灾更危险;火灾发生时列车火源位置应尽量停靠在两疏散口之间,且隧道内进行通风排烟;疏散口间距设置为300 m满足城际列车和地铁列车人员安全疏散要求。     

地铁过江隧道事故通风系统对火灾的影响研究

以某城市地铁过江隧道火灾为例,采用地铁环境模拟软件,计算和分析列车不同着火部位及隧道事故通风系统启动时间对火灾高温烟气分布的影响。结果表明,列车活塞风由于惯性作用将对火灾高温烟气控制产生一定的影响。车头着火时,列车活塞风有利于控制烟气回流,隧道事故通风系统启动越快有利于控制车头烟气温度的升高;车尾着火时,活塞风对控制火灾烟气向车头蔓延产生不利影响,事故通风系统立即启动使车尾烟气温度快速达到最高,可能产生轰燃现象,事故通风系统推迟启动使高温烟气快速向车头方向扩散,不利于人员逃生。建议加强列车车尾自身的消防灭火装置,提高人员灭火救援的自救意识。     

Experimental and numerical analyses of train-induced unsteady tunnel flow in subway

To analyze the unsteady three-dimensional flow in the subway tunnel caused by the passage of a train, both experimental and computational studies have been conducted. The experimental analysis of train-induced unsteady flow is conducted on a 1/20 scale model tunnel and the pressure and air velocity variations with time are presented. The three-dimensional unsteady numerical analysis using the sharp interface method for the moving boundary of an immersed solid was carried out for the same geometric configurations as the experimental analysis. The predicted numerical model results show good agreement with the experimental data.