烟囱效应作用下隧道火灾发展特性研究

发布时间：2018-05-14 11:56

  本文选题：隧道火灾 + 烟囱效应　； 参考：《郑州大学》2015年硕士论文

【摘要】：随着人们对交通便利性越来越高的要求,隧道成为了缓解交通压力,缩短通行里程的有效方式之一。但是,近年来频繁发生的隧道火灾警示人们,如果不有效控制隧道内火灾的发展,将造成巨大的财产损失和人员伤亡。隧道狭长的内部结构和空间密闭性导致火灾发生后大量有毒高温气体聚积在隧道内,对后期救援工作带来一定困难。因此,研究隧道火灾发展特性和防排烟效果具有重要意义。本文根据相似原理建立了1:10小尺寸实验台,研究竖井对隧道火灾发展特性的影响,主要包括火源功率、顶棚下最高温度和烟气纵向温度分布。分别建立了无量纲火源功率、无量纲顶棚下最高温度随火源与竖井距离、竖井高度变化的预测模型。研究结果表明,无量纲火源功率随着火源距竖井距离的增大呈指数衰减。竖井对火源功率的影响可以分为两个区域:Ⅰ区为近竖井区;Ⅱ区为远竖井区。Ⅰ区的大小随竖井高度呈线性增长,符合公式**S?3.03?1.5H。在Ⅰ区:无量纲火源功率、无量纲顶棚下最高温度随竖井高度增加呈线性增长且斜率较大,当*S?1时,火源功率是无竖井工况的1.35倍。在Ⅱ区:无量纲火源功率、无量纲顶棚下最高温度随竖井高度增加变化不大。竖井的烟囱效应对隧道内烟气纵向分布有降温作用,下游烟气的温度降与S*符合指数衰减关系。通过变化竖井高度和火源距竖井距离,研究了竖井的排烟效果。结果表明,随着远离火源,到达竖井附近的烟气水平惯性力逐渐减小,导致竖井排出的烟气质量流率线性减小。竖井较低时,烟气受到的烟囱效应相对较小,热烟气主要在水平惯性力作用下从竖井口下游排出,排烟效率较低。竖井达到一定高度时,竖井高度大于了回流区域,此时较强的烟囱效应减弱了由于边界层导致的大尺度漩涡对排烟效果的影响,排烟烟质量流率线性增大,排烟效率增强。
[Abstract]:With the increasing demand of traffic convenience, tunnel has become one of the effective ways to relieve traffic pressure and shorten mileage. However, the frequent tunnel fires in recent years warn people that if the development of fire in the tunnel is not effectively controlled, it will cause huge property losses and casualties. The long and narrow internal structure and space sealing of the tunnel lead to the accumulation of a large number of toxic and high temperature gases in the tunnel after the fire, which brings some difficulties to the rescue work in the later stage. Therefore, it is of great significance to study the characteristics of tunnel fire development and smoke control. Based on the principle of similarity, a 1:10 small scale experimental bench is established to study the influence of shaft on tunnel fire development characteristics, including fire source power, maximum temperature under ceiling and longitudinal temperature distribution of flue gas. The prediction models of dimensionless fire source power and the maximum temperature under the dimensionless ceiling with the distance between the fire source and the shaft and the height of the shaft are established respectively. The results show that the dimensionless fire source power decreases exponentially with the increase of the distance from the fire source to the shaft. The influence of shaft on the power of fire source can be divided into two regions: area 鈪，

本文编号：1887752