Metro system as the most effective transportation method in urban area, greatly relieve the traffic pressure. The fire safety problem of metro system cannot be ignored as it is easy to develop into a large-area fire due to the relatively closed condition of the metro system. Double fire source is an important process in the development to large-area fire, however, there is still no relevant researches studying the flow characteristics and smoke movement under double fire sources with a metro train in the tunnel. This paper conducted a series of the full-scale numerical simulation to investigate the evolution of longitudinal temperature profile and maximum temperature rise under condition of double fire source with metro train in the tunnel. The velocity and temperature profile along the tunnel ceiling was measured and analyzed. It is found that (1) the longitudinal temperature distribution of tunnel fire smoke is still exponentially attenuated under different fire source separation distance with a metro train in the tunnel, and the decay coefficient decreases with the increase of fire source separation distance; (2) the maximum temperature rise of fire smoke under the tunnel ceiling decreases with the increase of the distance between the fire sources. Correlations were developed to describe the longitudinal temperature profile and maximum temperature rise under condition of double fire sources with a metro train in the tunnel through the analysis of the effect of additional air entrainment area, smoke interaction as well as the blockage effect of the metro train. The new findings in this paper can provide basic understanding of smoke movement under condition of double fire sources with a metro train in the tunnel, the proposed correlations can provide support for the safety operation of the metro system.

地铁系统是市区最有效的交通方式，大大缓解了交通压力。地铁系统的消防安全问题不容忽视，因为地铁系统相对封闭，很容易发展成大面积的火灾。双重火源是向大面积火势发展的重要过程，但是，在隧道中使用地铁列车的双重火源下的流动特性和烟气运动尚无相关研究。本文进行了一系列的全过程数值模拟，以研究在地铁双重火源的条件下，隧道纵向温度分布和最大温升的演变。测量并分析了沿隧道顶棚的速度和温度分布。研究发现：（1）在不同的火源分离距离下，随着隧道内地铁列车的出现，隧道火烟的纵向温度分布仍呈指数衰减，衰减系数随火源分离距离的增加而减小。（2）隧道顶下火烟的最大温升随火源之间距离的增加而减小。通过分析额外的空气夹带面积，烟气相互作用以及地铁列车的阻塞效应，建立了相关性以描述地铁列车在隧道中双重火源条件下的纵向温度曲线和最大温度升高。 。