Numerical Simulation on Train Length Effect on Smoke Propagation in a Stopped Train Fire

Abstract

It is important to keep fire safety for subway system especially for subway tunnel. This paper selects a 2.2 km tunnel of Beijing subway as the research object, and studies fire scenario for a stopped train with natural ventilation. The multi-scale method where a three-dimensional field model and a one-dimensional network model are combined is used to simulate smoke propagation in a tunnel fire. The effects of train length on the smoke propagation, temperature and visibility distribution are analyzed. The results show that during the initial period of 120s, the influence of train length on temperature distribution, visibility distribution and smoke distribution is not obvious. However, after 120s period, smoke distribution becomes more concentrated with the increase of train length, and the impact of stack effect is more obvious. For a shorter train, the concentration of smoke is higher. The temperature distribution inside the 60 m train is higher than those of 120m and 160m trains.