纵向排烟V形坡隧道火灾烟流特性现场火灾试验研究

Field fire test on smoke flow characteristics of V-slope tunnel with longitudinal smoke exhaust

为验证全射流纵向排烟V形坡公路隧道火灾时通风排烟系统整体运行控制模式的有效性,并为防止火灾烟气对隧道洞口外人员安全的影响,依托济南黄河济泺路隧道开展全尺寸现场实体火灾试验,确定不同条件下烟气流动特性及烟气出洞口扩散情况。研究表明:V形坡隧道内发生火灾时,全射流纵向排烟系统整体运行有效;无机械通风时,在“烟囱效应”和自然风共同作用下,不同火源功率下烟气蔓延距离不同;近火源区域烟气温度呈脉冲形式,分层不明显,远火源区域竖向温度分层明显;机械通风时,不同火源功率下,风机产生的机械风作用到烟气前锋平均时间为15 s,均能完全控制住上游烟气逆流;烟气出洞口后,扩散距离与纵向风速呈正比关系。明确了隧道洞口外区域的人员安全距离。

In order to verify the effectiveness of the overall operation control mode of the ventilation and smoke exhaust system in V-slope highway tunnel during fire,and to prevent the impact of fire smoke on the safety of personnel outside the tunnel entrance,a full-scale on-site physical fire test was carried out in Jinan Huanghe Tunnel to determine the flow characteristics of smoke and the diffusion of smoke from the tunnel entrance under different conditions.The results showed that when a fire occured in V-slope tunnel,the full jet longitudinal smoke exhaust system could operate effec-tively.When there was no mechanical ventilation,under the joint action of“chimney effect”and natural wind,the smoke spread distance was different under different fire power.The smoke temperature near the fire source was in the form of pulse,and the stratification was not obvious,while the vertical temperature in the far fire source was obvious.In mechanical ventilation,under different fire power,the average time of mechanical wind generated by the fan acting on the flue gas front was 15 s,which could completely control the upstream flue gas counterflow.After the flue gas exits the hole,the diffusion distance was proportional to the longitudinal wind speed.The safety distance of personnel outside the tunnel entrance was defined.