活塞风作用下超长公路隧道火灾烟气蔓延特性研究

Study on smoke spread characteristics of super-long highway tunnel under piston wind

汽车在隧道中行驶时会产生活塞风,有效利用活塞风可降低机械排烟系统的成本和能耗。本文首先进行了理论分析,然后通过计算流体动力学软件对活塞风作用下公路隧道的火灾烟气蔓延特性进行研究。数值模拟探究了不同活塞风速对于隧道中不同火源功率(10、30、50 MW)情况下烟气层运动、温度场和流速场分布的影响。研究结果表明,近期、远期的活塞风速衰减模型在不同火源功率时,烟气层运动、温度场和流速场变化规律基本相同,随着火源功率增大,烟气回流到隧道入口的时间更短,隧道内流速场发生变化的时间越晚。

The piston wind would be produced when the vehicle is driving in the tunnel,the effective use of piston air could reduce the cost and energy consumption of mechanical smoke extraction system.In this paper,the theoretical analysis was carried out first,and then the smoke spread characteristics of the highway tunnel under piston wind were investigated by using the computational fluid dynamics software.Numerical simulation was carried out to explore the influence of different piston wind speeds on smoke layer movement,temperature field and velocity field distribution under different heat release rate(10,30,50 MW)in the tunnel.The results showed that the recent and long-term piston wind speed attenuation model have the same variation rules of smoke layer movement,temperature field and flow velocity field under different heat release rates.With the heat release rate became larger,the time for smoke to return to the tunnel entrance was shorter,and the time for the flow velocity field to change was later.