城市交通隧道坡度对火灾烟气扩散影响研究

利用大涡模拟方法研究城市交通隧道火灾自然通风下烟气的扩散规律,重点研究隧道的坡度对烟气羽流的影响。研究坡度在0-5%范围内的隧道内烟气层横向以及纵向温度场分布以及火源拱顶处最高温度随时间的变化规律,并与坡度为零的隧道火灾的烟气模拟结果进行比较。研究表明：5%坡度对烟气纵向分布影响较大,尤其在火源下游的上坡方向,烟气层沉降快。坡度使烟气最高温度点火源下游偏移,但最高温度值变化不大。研究结果对于研究城市交通隧道的消防设计以及人员疏散提供参考。

Study on the slope effect on smoke propagation in urban traffic tunnel

The smoke propagation in an urban traffic tunnel fire under natural ventilation was studied by large eddy simulation（LES）.The tunnel slope effect on smoke propagation was emphasized.For a tunnel with slopes range from 0-5% slope,the transverse and longitudinal temperature distributions of smoke layer,the highest temperature on tunnel ceiling were calculated.These numerical results are compared with corresponding horizontal tunnel.It was found that the slope had a great effect on smoke temperature along longitudinal direction,especially in the ascending part downstream of fire source,smoke layer descendd more quickly to a safety height.The highest temperature position under tunnel ceiling departured from the point of fire source on the descending side.But the highest temperature of 5% slope did not vary greatly as compared to horizontal tunnel.These results can provide reference on fire protection design of urban traffic tunnel.