Research On Optimization Of The Cross-section Of The Single-track High Speed Railway Tunnel And Tunnel Hood

Since 1960's, high-speed railway has grown up in developed countries and railway has developed into a new age. China will develop high-speed railway in a large scale. When train travels across the tunnel at a high speed, it will cause obvious pressure fluctuation in tunnel and micro-pressure wave radiated from the exit of the tunnel, which will influence passengers' comfort and environment around a tunnel. This thesis is based on the developing project of "Testing and research on the related technology of the aerodynamic effect in the high speed railway tunnel", which is from the national railway department and also based on the project of "The research on the micro-pressure wave and tunnel hood around the gate of the tunnel in YuHuai railway with the speed of 200km/h" ,which is from the second surveyed and design institute of China Railways. Research on the lucubration of tunnel aerodynamic effect's mechanism and corresponding alleviation measure was carried out.Model testing and digital simulation were used to carry on the research. The model testing is carried out with the "High-Speed railway model projecting testing stand" in South West Jiaotong University. Three-dimensional viscosity, comprehensible, isentropic, transient flow Navier— Stokes equation was used in the digital simulation. Finite volume method is used to discrete the element. Software "Fluent" is used to carry out the calculation.When high-speed train travels across tunnel without the tunnel hood, initial micro-pressure wave is the origin of the internal pressure wave in the tunnel and the origin of the micro-pressure around the exit of the tunnel. Through the digital simulations and model testing, maximum initial micro-pressure wave and pressure gradient were investigated. The relationship among the maximum pressure, pressure gradient, train speed, train/tunnel area ratio, train nose length/height ration is obtained.Through model testing and digital simulations the maximum micro-pressure around the non-hood tunnel exit was investigated. The cross-sectionof the single-track railway tunnel was optimized according to the standard of the micro-wave.The research of enlarged transect windowless hoods was carried out with the help of digital simulation. The influence mechanism of the hood length and enlarged transect ratio on the first compression wave was made clear and the parameter for calculating optimum enlarged transect ratio was given out.With the help of the digital simulations, enlarged transect window hoods were investigated. With the help of the digital simulations, the action mechanism of windowed hoods was made clear. A detailed study has been made on the different vent pattern, different vent position and different vent ratio of the tunnel with one and double hydraulic radius. The optimized vent ratio and vent position were given out for the enlarged transect window hoods of the one and double hydraulic radius tunnel.