【作者】 钟委；

【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， 2007， 博士

【摘要】 地铁是城市最重要的公共交通工具之一，是今后城市公共交通的主要发展方向，也是城市现代化的重要标志。目前全世界已有越来越多的城市建成或正在建设自己的地铁交通系统，国内也正处于地铁交通系统的飞速发展阶段。地铁在给人们带来了便利的出行方式的同时，也给火灾防治带来了许多新的问题。近年来陆续发生了多起重特大地铁火灾，造成了惨重的人员伤亡和财产损失。统计结果表明，造成地铁火灾中人员伤亡的主要因素是由于不完全燃烧所产生的有毒的高温烟气。因此，研究地铁火灾的烟气流动特点与烟气控制方法具有重要的意义。地铁站是一类特殊的地下建筑形式，通常由站厅层和若干站台层组成，地铁站各层均为狭长型结构，且各层之间存在一定的高度差。因此地铁站火灾中的烟气流动相比于一般建筑的烟气流动更加特殊。本文在分析了地铁站火灾烟气流动过程的基础上，采用理论分析、小尺寸模型实验、全尺寸实验与数值模拟相结合的方法对地铁站内的烟气流动与控制开展了研究，论文的具体工作如下：采用1／8的相似比建立了7.5m×1.5m×0.6m的小尺寸地铁站模型实验台，在实验台内开展了大量基础性实验。并在深圳地铁会展中心站和岗厦站的三个站台内开展了全尺寸火灾实验，检验了实际地铁站内的机械排烟和正压送风挡烟效果，为地铁火灾研究积累了宝贵的实验数据。建立了地铁站火灾时顶棚射流最高温度的预测模型。Alpert模型中考虑的是顶棚射流未受限的情况，对于地铁站火灾这种情况其预测值偏低。本文通过小尺寸实验数据，得到了对于宽高比为3的地铁站顶棚射流最高温度的修正系数。并确定出了随火源距端部壁面距离的增加，顶棚射流最高温度的衰减规律。通过理论推导得出了站厅正压送风挡烟临界风速的预测模型，发现当火源功率增大到一定值后，临界风速将达到一个最大临界风速值。并将预测结果与全尺寸试验结果和FDS的计算值进行了对比。结果表明，论文所建立的模型的预测结果与全尺寸试验结果和FDS计算值符合得较好。分析了站厅火灾时，站厅两侧楼梯对火灾烟气的竞争现象，对陈法林的研究结果进行了修正。并采用小尺寸模型试验和FDS数值模拟对理论分析的结果进行了验证。本文通过在一蓄烟池内开展机械排烟实验，研究了在排烟口水平布置条件下，不同排烟口高度和排烟口风速对机械排烟效率的影响。验证了Hinckley模型在预测机械排烟时发生吸穿现象的有效性。采用FDS对会展中心站地下三层侧式站台不同排烟口高度下的排烟效果进行了数值模拟，根据实验和模拟计算提出了地铁站内适合的排烟口高度和排烟口风速。在全尺寸实验的基础上通过竖直模拟对地铁站机械排烟时的排烟死角现象进行了研究，提出了改进排烟效果的补风方案。并对于地铁站内的四种排烟模式进行了对比，根据模拟计算结果确定出了最佳的排烟模式。更多还原

【Abstract】 Subway is one of the most important public transportation systems in cities. More and more subway systems is built in the world and it is deemed as the symbol of modernization of a city. In China, there are also many subways systems which are being built or in construction in recent years. Subway provides convenient transportation for cities, but also brings many new fire safety problems. Several disastrous subway fires have occurred in recent years, with a great number of victims and substantive loss of properties. Statistics showed that the toxic and hot smoke released due to incomplete combustion were the most fatal factor in subway fires. So, it is very important to study the characteristics and the control strategy of smoke spread in a subway fire.Subway station is a kind of special underground building, it is constitute with a waiting hall floor and a platform floor. Smoke movement in a subway station is more complex than that in a normal compartment. In the thesis, the characteristics and the control strategy of smoke spread are studied by theoretical analysis, small scale experiments, full scale experiments and numerical simulation. Works include:A small scale model of subway station with scale factor of 1/8 was constructed with dimensions of 7.5m×1.5m×0.6m. Full scale experiments were also conducted in three different platforms belonging to exhibition center station and Gangxia station in Shenzhen subway, to validate the efficiency of smoke management system, especially the pressurization effects, in subway station. These experiments provide important data for subway fire research.A model was built for predicting the maximal temperature of ceiling jet in a subway station. The Alpert model is applicable for the situation that the ceiling jet flow is not confined. It was found that in a case of subway fire with a confined ceiling jet; the prediction of Alpert model is some lower. The modification coefficient for the maximal temperature of ceiling jet in case of the ratio of platform’s width and height equal to 3 was calculated based on the small scale experiments. The decay of the maximum ceiling jet temperature along with the increase of distance between fire and platform wall was also discovered.A model for predicting the critical velocity of pressurization in subway hall was established by theoretical analysis. It was found that when the heat release rate increases to a certain value, the critical velocity would reach to a maximum value, and does not increase with the increase of the heart release rate any more. The model was further verified by full scale experiments and CFD simulation results. It was proved to be reliable with predictions to be in good agreement with both the measured value in the full scale experiments and predictions by FDS.The characteristics of smoke competition between stairs exist in the two side of subway hall was studied. The former work by Chen Falin’s based on the theoretic analysis was modified. Small scale experiments and numerical simulation were conducted to validate the analysis.The smoke exhaust efficiency with different horizontal vent opening heights and velocities was also studied by experiments in a smoke reservoir. The Hinckley model was validated to be reliable in predicting the occurrence of plugholing. FDS simulations was also performed to study the effect of smoke exhaust in the side platform of exhibition center station, the proper vent height and velocity was found according to the experimental data and simulation results. The blind area of smoke exhaust in platform is also found by full scale experiments. An air supply strategy was put forward to solve this problem. The exhaust efficiency under four smoke control schemes were compared by numerical simulation with the best one recommended.更多还原