Numerical studies on ventilation modes in underground railway tunnel fire

Presents several ordinary ventilation and smoke extraction modes，and simulates the most complex one of them. The results show that for the single-track shield tunnel in actual projects，the longitudinal ventilation velocity of 2.6~2.9 m/s can effectively prevent smoke from counter flow at a heat release rate of 10 MW; when the tunnel sector on fire with a longitudinal velocity of 2.9 m/s and the unfired tunnel sector with the velocity of 1~1.5 m/s from both ends，there is an air flow with the velocity of 6 m/s to the tunnel on fire in the connected tunnel，so the smoke diffusion to the unfired tunnel is effectively prevented，and the security of evacuation is ensured.