Aerodynamic Study On The High-Speed Railway Tunnel With Large Cross-Sections

The aerodynamics effect generated by a high-speed train passing through a tunnel is the basic question which the high-speed railroad tunnel designs faces nowatime. At a higher speed, the train entry into a tunnel will cause obvious pressure fluctuation in tunnel and micro-pressure wave radiated from the exit of the tunnel, and the transient pressure peak value, the pressure gradient and the export micro pressure wave are the major impact factors, which directly decide the traveling security, passengers' comfortable as well as the tunnel export's environment question. In order to meet the need of our country railroad's development, lucubration of tunnel aerodynamic effect's spread abroad rules and corresponding alleviation measure is very necessary.In view of our country's high-speed railway development plan, this article mainly analysis the spread rule of pressure wave in high-speed railway tunnel about 4 different large-cross sections tunnels (single or double track) with the help of the model experiment, the theory reasoning and the numerical simulation, and discusses the infection that tunnels aerodynamics effect generated by tunnel cross area and the hood, and the complex press field which is made by trains crossing in double-track tunnels, as well as the influence factors and alleviation measures. Contrasting the exports micro pressure wave by the theory reasoning and the numerical computation, the numerical computation's reliability has been confirmed;obtains the relation of the tunnel cross section, train's speed with the transient pressure and the pressure gradient, confirms that when the train's speed is higher than 350km/h in double-track tunnels, the tunnel cross-section must be enlarged to 100m~2. Discusses the classic hoods forms, obtains that the windowless hoods is to be the most superior form and the length of the hood has important function which would reduce the aerodynamics effect. The complex pressure field which is made in double-track tunnels when trains' passing cross is related to the tunnel length, passing speed, as well as the crossing position, the different speeds correspondence has the most disadvantageous tunnel length, which would cause to double the crossing pressure wave which would affect traveling security. Analyzes the influence factors of the tunnel aerodynamics effect, it is discovered that the tunnel length, the railway bed form as well as the front of a train shape have the important influence regarding to the pressure wave diffusion.