车辆阻塞效应下隧道火灾烟气温度及烟气逆流长度变化规律研究

摘要

Numerical simulation using FDS was conducted to systematically study the variation of smoke temperature beneath the tunnel ceiling and smoke back-layering length in tunnel fires with vehicle blockage,when the height of fire source and the longitudinal ventilation velocity were changed.Two blocked scenarios were considered: one fixed-size vehicle obstruction blocked and two fixed-size vehicle obstructions along the longitudinal tunnel blocked.The smoke temperature beneath ceiling shows the same variation trend in these two vehicular blockage cases: the temperature increases with the rise of the height of fire source.The temperature is measured lower with two vehicles blocked.However,the back-layering lengths have different trends in these two vehicular blockage cases.It is concluded that the higher the height of fire source is,the longer the back-layering length becomes with one vehicle blocked.The higher the height of fire source is,the shorter the back-layering length becomes with two vehicles blocked.%通过数值模拟方法对车辆阻塞效应下的隧道火灾烟气温度及烟气逆流长度的变化规律进行了研究.主要分两种车辆阻塞效应讨论:1辆设定大小车辆障碍物阻塞;2辆设定大小车辆障碍物阻塞,且在同一车道.通过改变火源高度、纵向通风速度探究了车辆阻塞效应下隧道火灾烟气温度及烟气逆流长度的变化规律.结果表明:两种车辆阻塞效应下,随着火源高度的升高,隧道内顶棚烟气温度的变化规律相同:随火源高度的升高而增大.2辆车辆阻塞下的隧道顶棚烟气温度略低;两种车辆阻塞效应下,随着火源高度的升高,隧道内烟气逆流长度的变化规律不同.1辆车辆阻塞下烟气逆流长度随火源高度的升高而增大,而2辆车辆阻塞效应下烟气逆流长度随火源高度的升高而减小.