阻塞条件下地铁隧道坡度对烟气逆流长度影响研究

Slope effect on the back-layering length in subway tunnel fires with blockage

在隧道纵向通风系统设计中,烟气逆流长度是至关重要的参数,传统的理论预测模型多适用于公路隧道,对阻塞条件下有坡度的地铁隧道烟气逆流长度的研究较少。通过理论分析、缩尺寸实验和FDS数值模拟,推导了适用于阻塞条件下有坡度的地铁隧道的无量纲烟气逆流长度模型,得到了烟气逆流长度随坡度的变化规律。研究结果表明,基于FDS模拟的水平地铁隧道烟气逆流长度与实验结果变化规律基本一致,该FDS模型可以研究不同坡度工况,且逆流长度随着坡度的增加呈增加趋势。

The back-layering length of smoke is an important parameter in longitudinal ventilation design. Previous studies focused on the road tunnels while there is few researches on the back-layering length of smoke in the in clined subway tunnels with blockage. By theoretical analysis, small size experiment and FDS simulation, this paper deduced the dimensionless expression of back-layering length in tunnel fire, which fits for the inclined subway tunnels with blockage. Moreover, the change rule of back-layering length with different slopes is obtained. The results show that the back-layering length of smoke in horizontal subway tunnel with blockage agrees well with the results of FDS simulation, so this model can study the conditions of different slopes; with the increase of slope, the back-layering length increases correspondingly.