Abstract: While highspeed railways have been built and operated worldwide, superhighspeed railways will become one of the development trends of rail transit, as a fast, comfortable, and energysaving mode of transportation. As train speed increases, the aerodynamic drag of trains increases significantly. To effectively reduce the aerodynamic drag and realize the superhighspeed traffic, evacuated tube transportation arises at the historic moment. The evacuated tube parameters have always been one of the focuses of evacuated tube transportation. To clarify the relationship between evacuated tube parameters and train speed, and obtain a simple and applicable design method of evacuated tube parameters, in this paper, the aerodynamic drag of trains traveling in standard highspeed railway tunnel at the speed of 350 km/h is taken as the criterion, and detailed researches are conducted on the mutual influence of blockage ratio, train speed, and internal tube pressure based on Tomoshige Hara Theory. Moreover, the theoretical values of the aerodynamic drag of trains traveling in evacuated tube are compared with that of numerical results. The research results show that: (1) The theoretical value nearly fits the numerical one. Therefore, the aerodynamic drag characteristics of evacuated tube transportation trains can be analyzed based on Tomoshige Hara Theory. (2) A parameter design method and parameter selection curve of evacuated tube based on the aerodynamic drag of highspeed trains is given, which can provide theoretical guidance for the selection of working parameters of evacuated tube.

Key words: supperhighspeed trains, evacuated tube, aerodynamic drag, internal tube pressure, blockage ratio