【作者】 林琳；

【导师】 王洪德；

【作者基本信息】 大连交通大学 ， 环境科学， 2010， 硕士

【摘要】 随着世界范围内城市化发展的进程,城市人口逐渐上升,交通问题也日趋严重。再加上快节奏的生活方式,人们对于交通工具的要求也愈来愈高。地铁因其安全、舒适、载客量大、快速、准点、低耗能、少污染的特点,被称为“绿色交通”,越来越受到青睐。正因如此,地铁成为人流比较集中的地方,特别是在上下班的出行高峰期,人员密度高,而它与外界的联系主要为出入口,环境密闭,人员密集,发生火灾时,不仅火势蔓延快,而且积聚的高温浓烟很难自然排除,严重威胁乘客、地铁职工和抢险救援人员的生命安全。经调查表明地铁发生火灾时造成的人员伤亡,绝大多数是因为烟气中毒和窒息所致。因此,地铁站内合理有效的通风排烟设置对于减少人员伤亡和财产损失具有极为重要的意义。对于受限空间火灾的研究,主要有实验研究和数值模拟研究。两者相比,数值模拟研究具有投资小,周期短,可重复性好的优点。目前在火灾烟气流动的模拟研究方面比较占优势的,就是基于CFD(计算流体力学)的数值模拟方法。本文就是利用CFD软件之一——FLUENT软件对烟气的流动进行数值模拟。FLUENT可用于计算流体的流动、传质传热、燃烧等化学反应过程,同时具有网格自适应功能,还可简单地对计算结果进行后处理,因此在各行业都得到广泛应用。地铁火灾中烟气的流动属于三维非稳态的湍流流动过程。本文在对地铁站台火灾的可能性及可燃物分析的基础上,建立了用于地铁站台火灾中烟气流动模拟的数学模型。并以天津某岛式地铁站台为研究对象,根据站台的实际尺寸建立了地铁站台的物理几何模型,并利用FLUENT软件,分别对站台内不同着火点及火源强度、不同的通风排烟模式下的火灾烟气流动情况进行数值模拟,得到站台中央或一端着火时,烟气在不同时间段内的温度情况,以及烟气的浓度分布。最后利用tecplot软件对其结果进行后处理。研究结果表明,当采用机械排烟方式时可以降低烟气的温度和扩散速度,有助于站台内人员的安全疏散。更多还原

【Abstract】 As the development of urbanization, urban population increases rapidly which results in serious transportation problems. Besides, there is an increasing demand for transportation tools in the city. Subway, which is regarded as the“green transportation”for its safety, comfort, capacity, speed, punctuation, low power consumption, and low population, is more and more popular. Therefore, subway becomes a place with a rather high flow rate, especially in rush hours with a rather high density, but as the main connection with outside world, exits are airtight and with large stream of people. In case of fire, it not only spreads quickly, but accumulates intense smoke with high temperature. The smoke is hard to be removed, which would threat the safety of the passengers, staff and rescuers. According to the survey, the majority of injuries in the fire are due to the smoke poisoning and suffocation. Therefore, ventilation equipment plays a very importation role in the casualty’s reduction and property loss.The researches of limited space fire are mainly experimental research and numerical simulation. Comparing with the previous one, numerical simulation is characterized by low investment, minor cycle and low repetitiveness. At present, the numerical simulation based on CFD is popular in the smoke flow research. This paper builds the numerical simulation of smoke flow by FLUENT software. The FLUENT can be used to calculate the liquid flow, heat and mass transfer, combustion and other chemical reaction, besides, it has mesh adapting and result processing functions.The flow of subway fire smoke is three- dimensional non-static turbulent flow. Based on the analysis of the causes of fire and fuel, this paper establishes a mathematical model to simulate the smoke flow in the subway station. The research object is a subway station in Tianjin. According to the real size of the subway station, the author establishes physical geometric model. The numerical simulation is built according to different ignition points, ignition source strengths and ventilation models. The temperature and density distributions in case of fire in a certain period are obtained. At last, the result processing is gained by tecplot. Studies show that when the mechanical smoke venting is used, the smoke temperature, and spreading speed can be reduced and this would contribute to the safe escape.更多还原