Abstract: At present, there are just general restrictions of wind velocity on the evacuation section (stairs &elevator entrance) in the subway platform referring to the relevant technical codes of China. Therefore, the Computational Fluid Dynamics (CFD) simulation and field test were conducted to elaborate the flow characteristics of the section. On the ventilation mode of platform fire case,it was found typical stratification phenomenon along the height, namely, boundary zone, main stream zone, decay zone and reverse flow zone from the bottom to the top. The evacuated people will mainly be active in the main stream zone with the wind velocity as high as 3~6 m/s, which benefits for the smoke control and fresh air supply. The small area of reverse flow zone on the top is formed due to the divergent effect of the flow downwards, and the potential risk of smoke entrainment should be noticed. Furthermore, the flow direction should be judged in the wind velocity test of the evacuation section in the subway platform.

Key words: subway platform, evacuation section, flow characteristic, smoke characteristic