长大斜坡地铁隧道火灾通风研究

发布时间：2018-01-20 03:30

本文关键词： 坡度隧道数值模拟温度能见度　出处：《西南交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着我国地铁隧道事业的发展,由于自然环境、地理因素的限制,隧道不可避免的存在坡度。另外,由于在隧道内列车自身发生火灾的位置具有不确定性,列车位于隧道内的位置也不确定,加之隧道坡度形成的烟囱效应,使隧道火灾的救援更加复杂。本文以乌鲁木齐市地铁1号线为研究对象,运用计算流体力学、传热学、燃烧学和隧道通风基本理论,确定数值计算方程,建立相应的隧道火灾烟气流动的三维数值模型,对列车不同部位发生火灾及隧道坡度和火灾规模对隧道内各参数的影响进行分析。通过对无通风工况下列车位于隧道中部,列车中部发生火灾时坡度隧道进行模拟,分析隧道内温度、烟气分布及能见度的情况,研究结果表明发生火灾时隧道拱顶温度、人高温度和人高能见度都不满足隧道火灾通风标准,故隧道内发生火灾必须进行机械通风；进而根据列车不同位置发生火灾,分析不同通风风速时隧道内纵向烟气蔓延规律及温度分布,得出各着火点下的竖井最小通风量和最小隧道通风风速,以及此工况下隧道温度、烟气及能见度的分布情况。由于列车头部发生火灾时需额外克服坡度造成的影响,故发现列车头部发生火灾时所需通风风速最大。对于列车中部和尾部发生火灾的情况,由于中部时列车的阻塞使流过列车所在隧道区域的通风风速增加,同时火源由于隧道阻塞在上升过程中的空气卷吸量也大大减小,因此火灾所需通风风速比列车尾部时发生火灾时相应减小。对于列车位于隧道低端、中部和高端发生火灾的情况,得出不同隧道位置对隧道内通风风速影响不大。通过对不同坡度、不同火灾规模的隧道模型进行模拟,确定各种工况下的最小隧道通风风速,并对此情况下隧道内的温度、烟气分布及能见度进行研究,分析坡度及火灾规模对隧道火灾通风的影响,得出同一火灾规模,在下坡隧道内,随着隧道坡度的增大,所需隧道通风风速逐渐增加,上坡隧道内则相反。而且在一定的隧道坡度下,随着火灾规模的增大,所需通风风速逐渐增大。
[Abstract]:With the development of subway tunnel in China, because of the restriction of natural environment and geographical factors, the slope of tunnel is inevitable. In addition, the location of train fire in tunnel is uncertain. The location of the train in the tunnel is also uncertain and the chimney effect caused by the slope of the tunnel makes the rescue of tunnel fire more complicated. This paper takes Urumqi Metro Line 1 as the research object and uses computational fluid dynamics. Heat transfer theory, combustion theory and basic theory of tunnel ventilation are used to determine the numerical equations and to establish the corresponding three-dimensional numerical model of smoke flow in tunnel fire. The effects of fire on different parts of the train and the slope and fire scale of the tunnel on the parameters of the tunnel are analyzed. The train is located in the middle of the tunnel under the condition of no ventilation. In the middle of the train fire, the slope tunnel is simulated to analyze the temperature, smoke distribution and visibility in the tunnel. The results show that the tunnel vault temperature occurs when the fire occurs. Both high temperature and high visibility do not meet the ventilation standard of tunnel fire, so mechanical ventilation must be carried out in tunnel fire. Then according to the different locations of the train fire, the longitudinal smoke spread law and temperature distribution in the tunnel with different ventilation wind speed are analyzed, and the minimum ventilation volume and the minimum tunnel ventilation velocity of the shaft under each ignition point are obtained. And the distribution of tunnel temperature, smoke and visibility under this condition. It is found that the ventilation wind speed is the largest when the train fire occurs at the head of the train. For the fire in the middle and rear of the train, the ventilation wind speed in the tunnel area where the train flows increases due to the congestion of the train in the middle part of the train. At the same time, the amount of air entrainment in the rising process of the fire source is also greatly reduced because of the tunnel obstruction, so the ventilation wind speed required by the fire is smaller than that at the rear of the train when the fire occurs. The train is located at the low end of the tunnel. It is concluded that different tunnel locations have little effect on the ventilation wind speed in the middle and high end of the tunnel. The tunnel models with different slope and fire scale are simulated. The minimum wind speed of tunnel ventilation is determined under various working conditions, and the influence of slope and fire scale on tunnel fire ventilation is analyzed by studying the temperature, smoke distribution and visibility in the tunnel. Get the same fire scale, in the downhill tunnel, with the increase of tunnel slope, the required tunnel ventilation wind speed increases gradually, the slope tunnel is opposite, and in a certain slope, with the increase of fire scale. The required ventilation wind speed gradually increases.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U453.5;U231.96

【引证文献】