既有地铁车站纵向通风烟气控制模式试验研究

Experimental study on smoke control mode of longitudinal ventilation in existing subway station

在北京某地铁车站开展现场试验,对不同烟气控制条件下烟气蔓延规律及楼梯口向下气流速度进行分析研究,同时利用FDS建立对应实际尺寸的数值模拟模型,增加烟气控制模式改变的工况,基于判断能见度危险来临时间对站台排烟能力展开分析研究。研究表明:针对不同烟气控制模式,烟气蔓延规律不尽一致,对于该既有车站而言开启全部风机及仅开启1号风机会造成楼梯口负压情形,即站台发生火灾烟气不会蔓延至站厅;分析楼梯口断面向下气流速度,可知开启全部风机时,楼梯口风速满足规范的楼梯口向下气流速度1.5 m/s的要求,而仅开启1号风机,一侧站台无法满足规范要求;在烟气蔓延规律分析及断面风速分析的基础上,可知1号风机对车站安全起主要作用;结合楼梯口断面风速试验数据与能见度危险来临时间模拟数据,可知开启全部风机相较仅开启1号风机大幅度提升了站厅安全性,但对站台排烟能力提升作用较小。

By the experiment on the existing railway station in Bei⁃jing,the smoke spread law and downdraft velocity under different smoke control conditions are analyzed.At the same time,the nu⁃merical simulation model corresponding to the actual size is estab⁃lished by FDS,and the working condition of smoke control mode change is added.Based on the available safe egress time judgment of the visibility,the smoke exhaust capacity in platform is stud⁃ied.The results show that:for different smoke control modes,the smoke spreading law is not consistent.For the existing station,opening all fans and only opening No.1 fan will cause negative pressure at the staircase,that is,the smoke from the fire on the platform will not spread to the station hall;the analysis of the downdraft airflow velocity of the staircase section shows that the opening of all fans meets the requirements of the standard down⁃draft airflow velocity of the staircase of 1.5 m/s,while only open⁃ing No.1 fan,one side of the platform cannot meet the require⁃ments of the standard;on the basis of the analysis of the smoke spreading law and the section wind speed,it is known that No.1 fan plays a main role in the station safety;combined with the test data of the staircase section wind speed and the simulated data of the available safe egress time judgment of the visibility,it is known that opening all fans greatly improves the safety of the sta⁃tion hall compared with only opening No.1 fan,but has little ef⁃fect on the smoke exhaust capacity of the station.