隧道火灾自然通风最不利火源位置的研究

Study on the worst fire location in tunnel with natural ventilation

为了确定排烟系统设计参数和更好地保障人员安全疏散,开展1∶20的缩尺模型试验,研究隧道内6种不同火源位置、4种火源热释放率的火灾对隧道纵向烟气温度分布的影响,通过对火源段烟气温度的分析确定自然通风条件下隧道火灾最不利火源位置。结果表明:火源外边缘位于孔口内侧时,不同火源位置对火源段的烟气温度影响不大;火源外边缘越过孔口内侧壁时,火源段内的烟气温度显著下降;火源最不利位置为火源外边缘位于孔口内侧壁正下方。

In order to determine the design parameters of the smoke exhaust system and ensure the safe escape of personnel better,a series of 1∶20 scale model tests were carried out.The effects of 6 different fire source locations and 4 different fire source heat release rates(HRR) on the longitudinal smoke temperature distribution of the tunnel were studied.Through the analysis of the smoke temperature in the fire source section,the worst fire source location of the tunnel fire under natural ventilation conditions was determined.The results showed that: When the outer edge of the fire source locates inside the opening,the position of different fire sources has little effect on the temperature of the smoke in the fire source section;When the outer edge of the fire source crosses the inner side wall of the opening,the temperature of the smoke in the fire source section drops significantly;The most worst position of the fire source is when the outer edge of the fire source is directly below the inner side wall of the opening.