Study On The Influence To Aerodynamic Effect Of High-Speed Railway Tunnel With Different Shaft Height

The high-speed railway is paid more attention to each country of the world by characteristics of its safety and reliability and high efficiency and low occupancy land and lighter pollution to the environment and economic efficiency and advanced technology. Our country is carrying on the high-speed railway construction on a large scale at present. When the train passed the tunnel with high speed will cause pressure fluctuation obviously and micro-pressure wave radiated from the exit of the tunnel, which will affect the comfort of the passengers on the train and the environment around the tunnel. This paper relied on the item of national high technology development project, which was undertaken by Southwest Jiaotong University to study the engineering techniques problems of the tunnel through the Huangpu River in the magnetic suspension railway from Shanghai to Hangzhou, and aerodynamic effects were deeply studied by using computational fluid dynamics analysis software FLUENT when the high-speed train passed through a tunnel with different height of the shaft at a velocity of 200-350km per hour.The numerical simulate method of the high-speed train passed through a tunnel with shaft was established according to the flow field features generated by a high-speed train entering into tunnels with shaft and the mathematics physical model of air flows in the tunnel and shaft. In the simulation, taking the Navier-Stokes equations described by three-dimensional unsteady viscous compressible non-homentropic flow as the control equations, a cell-centered finite volume scheme for numerical integration of the Navier-Stokes equations was used for space discretization, and the preconditioned second-order accurate backward difference was adopted in time discretization. In addition, the walls of the tunnel and shaft were described with wall functions. The technology of sliding mesh were employed to simulate the high-speed train gone through a tunnel with a shaft. And the result of the field survey experiment was compared with the numerical calculation result according to the real size of western tunnel of Ueberlinger.The flow field given rise to the high-speed train passed through a tunnel with shaft were analysed with the help of numerical calculation, and the change of pressure and pressure gradient inside the tunnel with or without shaft were compared. The full course of pressure fluctuation when the high-speed train passed through a single line tunnel with shaft were investigated as well as the property of pressure field and speed field in this course. The distribution of three-dimensional pressure field and speed field surrounding the train and tunnel in different moment and different seat were also given out.By using theory analysis in combination with numerical calculation, the action mechanism that the single shaft reduced the aerodynamic effects of tunnel was explored. The numerical simulate computation were done carefully for the influences of the aerodynamic effects of high-speed railway tunnel with different height of shaft respectively. The influences of different height of shaft to the peak of pressure and pressure gradient induced by initial compression wave and the peak of micro-pressure wave radiated from the exit of the tunnel were studied under the different tunnel length and different train speed. And the micro-pressure wave radiated from the exit of the shaft were investigated by setting up monitoring points outside the exit of the shaft for the first time. The parameter optimization of shaft height was discussed on the foundation of alleviating the synthetical aerodynamic effects in tunnel.