双层隧道上层车道顶部单侧与双侧机械排烟的效果研究

Study on the effectiveness of single-sided and double-sided mechanical smoke exhaust in the upper lane of a double-layer Tunnel

为了探讨双层隧道上层车道顶部排烟时,单侧与双侧机械排烟对火灾烟气控制及蔓延的影响,采用FDS对某典型双层隧道在不同排烟控制模式下的烟气控制效果进行了对比研究。在说明模型合理性的基础上,对比分析了不同排烟风机开启模式下的烟气蔓延距离、排烟口处气体质量流率和温度变化规律。研究表明,开启隧道排烟道单侧风机和双侧风机时,排烟口处气体质量流率分布呈现不同规律,同时开启隧道两侧的排烟风机时烟气蔓延范围最小,是同等排烟量下只开启隧道下游一侧风机的47.8%~88.1%,且各排烟口处具有更低的平均温度,综合反映出同时开启隧道两侧的排烟风机具有更好的控烟效果。此外,探讨了在排烟道单侧和双侧排烟模式下隧道烟气蔓延范围随火源位置的变化规律。

To investigate the impact of single-sided and doublesided mechanical smoke exhaust on fire smoke control and spread at the upper lane in a double-deck tunnel,FDS was used to conduct a comparative study on the smoke control effectiveness in a typical double-deck tunnel under different exhaust control modes.Based on illustrating the rationality of the model,the smoke spreading distance,gas mass flow rate and temperature distribu⁃tion at the smoke exhaust vent were comparatively analyzed under different smoke exhaust fan opening modes.The study showed that the gas mass flow rate distribution at the smoke exhaust out⁃let shows different patterns when the exhaust fan is activated on the single-side or double-side.When the smoke exhaust fans on both sides of the tunnel are turned on,the smoke spread range is the smallest,which is 47.8%~88.1%of the exhaust fan on the downstream side of the tunnel are opened under the same smoke exhaust volume.And the average temperature at each smoke ex⁃haust outlet is lower,which comprehensively reflects that turning on the smoke exhaust fans on both sides of the tunnel has a better smoke control effect.In addition,the variation of the tunnel smoke spread range with the fire source position under the single-side and double-side smoke exhaust modes was also discussed.