基于PyroSim的斜井结构对隧道烟气蔓延特性影响的研究

Effects of slant sell structure on tunnel flue gas spread characteristics based on PyroSim

以大万山隧道为依托工程,基于PyroSim火灾模拟软件,探究自然排烟条件下斜井对火灾烟气蔓延特性的影响。通过模拟隧道火灾情景,分析了无纵向风时大万山隧道烟气蔓延规律及温度场、能见度分布情况,并设置无斜井隧道为对照组。结果表明,火灾发生时,受斜井浮力效应、风流密度等影响,烟气向斜井方向蔓延速度略高于火源对称位置烟气速度,但流经排烟口后速度、烟雾量显著降低,同时由于斜井的卷吸作用,大量热烟气汇集在排烟口中,使得周围区域形成涡流。斜井在隧道运营期间可以有效确保排烟效果,故研究斜井对隧道火灾烟气蔓延规律的影响对隧道火灾预防及应急处理具有深远意义。

Based on the Dawanshan Tunnel and PyroSim fire simulation software,this paper investigates the influence of inclined shaft on the fire smoke spreading characteristics under natural smoke exhaust conditions.In this paper,the smoke spreading law,temperature field and visibility distribution of Dawanshan Tunnel without longitudinal wind speed are analyzed by simulating the tunnel fire situation,and the tunnel without inclined shaft is set as the control group.The results show that when the fire occurs,due to the buoyancy effect of inclined shaft and the change of air flow density,the flue gas propagation speed in the direction of the inclined shaft is slightly higher than that in the symmetrical position of the fire source,but the speed and smoke volume decrease significantly after passing through the exhaust port.At the same time,due to the encoiling action of the inclined shaft,a large amount of hot flue gas gathers in the exhaust mouth,which makes the surrounding area form eddy currents.The inclined shaft can effectively ensure the smoke exhaust effect during the tunnel operation.Therefore,the influence study of the inclined shaft on the smoke propagation law of the tunnel fire has important significance for the prevention and emergency treatment of the tunnel fire.