纵向风对高海拔铁路隧道火灾烟气时空分布的影响

目前对高海拔铁路隧道火灾的研究较少。本文应用火灾动态仿真模拟软件(Fire Dynamic Simulation,FDS)对海拔500,3000 m铁路隧道内的火灾烟气蔓延进行了数值模拟分析,对比了高海拔环境低温、低压、低氧等显著特征及纵向风速对隧道火灾的影响。结果表明,在本文的火灾计算条件下海拔3000 m时隧道内的最高温度比低海拔时低24.8%,CO浓度增大30%~50%;海拔3000 m时随着纵向风速增加,拱顶最高温度显著下降,最大降幅达62.5%,且最高温度点向下游偏离火源区边缘上方;火源上游温度减小且升温范围逐渐减小,纵向风对上游烟气的“稀释”“阻拦”作用强于下游。

Influence of Longitudinal Wind on Temporal and Spatial Distribution of Fire Smoke in High Altitude Railway Tunnel

At present,there are few studies on high-altitude railway tunnel fires.The numerical simulation analysis of fire smoke spread in railway tunnels with altitude of 500 m and 3000 m was carried out.The influences of high-altitude environment such as low temperature,low pressure and low oxygen on tunnel fire were compared.The results show that the highest temperature at altitude of 3000 m is lower 24.8% than that at low altitude.The CO concentration increased by 30%~50%.The influences of four different longitudinal wind speeds on the development of fire smoke at altitude of 3000 m were compared.With the increase of longitudinal wind speed,the highest temperature of the vault is significantly decreased.The maximum drop is 62.5%,and the highest temperature point is downstream from the edge of the fire source area.The temperature upstream of the fire source decreases and the temperature rise range gradually decreases.The“dilution”and“blocking”effect of the vertical wind on the upstream smoke is stronger than the downstream.