Numerical Simulation of Fire Smoke Flow Characteristics in Subway Tunnel with Natural Ventilation

Understanding the characteristics of fire smoke flow in tunnel fire is very important for tunnel safety. Based on the compressible Navier-Stokes equations and Large Eddy Simulation (LES) turbulent model, distributions of temperature under the ceiling in metro tunnel with natural ventilation mode was simulated using CFD software FDS. Combining with practice of engineering structure of Chengdu Metro, fire smoke flow characteristics in subway tunnel with natural ventilation are researched on different space between ventilation shafts and size of ventilation shaft in this paper. The maximum heat release rate is 10 MW. By means of numerical simulation, we can have some useful conclusion. The smoke temperature under the ceiling varies with longitudinal different distance from fire source. The space between two neighboring shafts is the most important factor for personnel escape in fire tunnel. The maximum space is able to be got for any fixed size of shaft. With the buoyancy force, the height of ventilation shaft has some affect on temperature distributions.