Research On Aerodynamic Characteristics Of Subway Tunnels And Its Maximum Train Running Speed

In recent decade years, the problem of traffic congestion and environmental pollution in urban areas has been severer with development of China’s rapid urbanization. Underground subway is an effective way to solve the problem. Through the unique values of subway have been much developed, the maximum designing speed of subways was not considered in view of aerodynamic effects as well as comfort of passengers.The paper based on research project about aerodynamics of urban subway and station focuses on flowing characteristics of subway and maximum operating speed considering comforts of passengers using mutual authentication with model tests, theoretical analysis and numerical simulation method. The work would provide rational advice for future subways.The contents of the paper are listed as follows:1. Based on principles of aerodynamics, propagation behaviors of the pressure in tunnels and pressure inside and outside of the train are studied on. The numerical simulation of aerodynamic effects based on running speed with 100 km/h is also carried out. The paper presents an optimum net sectional area for tunnels when their designing speed is 100 km/h according to comfort of passengers. Besides, a maximum running speed for a tunnel section’s diameter of 5.4 m is also presented.2. Numerical simulation on aerodynamic effects of two sides of station when train’s running speed is 100 km/h is carried out. Aerodynamic effects at Platform Screen Door (PSD) and variations in running speeds at PSD and in tunnels are analyzed. The pressure field and speed field in the tunnel, especially at PSD are also analyzed based on train’s speed of 100 km/h, which provide guidelines for designing strength of PSD.3. The opening ways of cross passage way and middle shafts of tunnels are analyzed. The changes of pressure in the tunnel and the train are calculated. The numerical simulation on air field when train runs through the tunnel with shafts is carried out. An optimum scheme is presented for tunnels with middle shafts are presented when tunnel’s length is over 3 km.