Study of Fire Smoke Diffusion in Subway Tunnel by Large Eddy Simulation

A mathematical model has been built and Large Eddy Simulation(LES)method is adopted to pre- dict smoke propagation in the tunnel between the Ji-Shuitan and Gu-Lou subway stations in order to make fire risk assessment of tunnel fire in subway systems.This tunnel is a representative subway tunnel between two stations in the loop line of Beijing Subway Systems.The mass concentration distributions of smoke at different heights,smoke horizontal movement distance,spreading velocity under different operating schemes of tunnel exhaust fans are predicted.The smoke exhausted effects of tunnel ventilation fans are also testified.The re- suits show that the existing smoke exhaust system could reach the critical tunnel ventilation velocity under 5.0 MW fire condition and the smoke layer could be kept at a safety height for passenger's evacuation.The simu- lated results can be provided as a reference for tunnel reconstruction and devising passenger evacuation scheme.