纵向通风作用下公路隧道火灾烟气输运规律研究

Research on the Transport Law of Fire Smoke in Highway Tunnels under Vertical Ventilation

在我国交通发展过程中,公路隧道的地位越发显著,隧道火灾危害严重,特别是烟气运动情况对隧道安全至关重要.采用小尺寸模型试验和FDS数值模拟相结合的方法,模拟隧道内火灾发展和烟气输运情况,分析了火场中的火焰情况和烟气运动、温度等参数变化.研究结果表明:当隧道上游入口处的纵向风压由限制风速所需风压增大至临界风速所需风压后,逆流层逐渐消失,最终达到稳态流动模式时,烟气仅从火源的下游开口排出;火源上游的顶棚射流温度衰减要比下游快很多;为保证紧急情况下人员安全疏散,建议隧道火灾早期隧道内的纵向风速宜控制在1.4~1.9m/s.

Highway tunnels have become increasingly prominent in the development of transportation in China,and tunnel fires pose serious risks,especially the movement of smoke,which is crucial for tunnel safety.To this end,a combination of small-scale model experiments and FDS numerical simulation was used to simulate the development of fire and smoke transportation in the tunnel,and the flame situation,smoke movement,temperature and other parameter changes in the fire field were analyzed.The research results indicate that when the longitudinal wind pressure at the upstream entrance of the tunnel increases from the required wind pressure for limiting wind speed to the required wind pressure for critical wind speed,the countercurrent layer gradually disappears.Finally,when the steady-state flow mode is reached,the smoke is only discharged from the downstream opening of the fire source;the temperature attenuation of the ceiling jet upstream of the fire source is much faster than that downstream;to ensure the safe evacuation of personnel,it is recommended to control the longitudinal wind speed inside the tunnel in the early stages of tunnel fires between 1.4~1.9m/s.