Study on the Effect of Tunnel Opening and Air Shaft on Pressure Wave of High-speed Subway
Research purposes:In order to solve the problem of passenger discomfort caused by the sudden change of section when the subway vehicle drives from the open line into the tunnel opening at high speed and passes through the intermediate air shaft,the three-dimensional compressible viscous fluid N-S equation and the RNG k-ε dual equation turbulence model are used to study the aerodynamic effects of the intermediate air shaft opening,closing and taking different forms of cavity buffer structure working conditions on the subway tunnel.Research conclusions:(1)The unreasonable setting of the location of the intermediate air shaft will lead to the superposition of the expansion wave,which can be calculated according to the length of the train,the train running speed and other factors to find out the reasonable location of the intermediate air shaft.(2)The adoption of cross-section enlarged and flared buffer structure in the tunnel opening can make the maximum value of the pressure gradient on the surface of the compartment decrease by 29.3%and 38.2%,respectively.(3)Evaluated in accordance with the assessment indexes of human comfort in the current standards,the length of the pressure-relief section of the buffer structure at the tunnel mouth of the 140 km/h high-speed magnetic levitation train system is more reasonable to be set at two times the hydraulic diameter of the tunnel cross-section.(4)This study can provide a reference to optimize the problem of the aerodynamic effect of high-speed subway trains when they drive into the tunnel.
high speed subway trainsaerodynamicspressure wavelocation of air shaftbuffer structure