Experimental and Numerical Investigation of Bypass Tunnel on Piston Effect of Underground Subway Station

With the rapid growth of the infrastructure constructions in China, more and more metro lines have been built in recent years. The piston wind have a significant influence on the air temperature and the flow field of subway stations and tunnels. The bypass wind tunnel located on both side of the platform, which have great effect of shunt piston wind. This study conducted a train-induced experiment in Xia wafang (XWF) station of Tianjin metro line 1, and the air temperature and velocity data were recorded. Meanwhile, a train-induced numerical simulation was carried out for full-scaled model. The experimental data was compared with the CFD results to analyze the influence of bypass tunnel on the indoor environment and the comfort of passengers. The results indicate that the bypass tunnel can significantly reduce the air velocity of the waiting area and improve the comfort of passengers. The bypass tunnel play an important role in reducing the piston airflow entering the stations, and reducing the piston effect of the station environment.