The effect for Tunnel Section Area to Running Resistance of High Speed Train

초록

Aerodynamic drag has great effect on maximum speed as well as the energy consumption of the high-speed train because its occupation in running resistance gets larger as train runs faster. And it is also well known that the running resistance in tunnel is much larger than that in open air due to the blockage ratio of the train in tunnel. Thus the tunnel factor which is the ratio of the tunnel drag by the open air drag is very important to design high speed train. In this paper, the resistance to motion of the Korean high speed train (HEMU-430X: High-speed Electric Multiple Unit-430km/h eXperiment) was estimated on the basis of coasting test runs. The running resistance in open air is estimated up to 400 km/h and the aerodynamic drag which is proportional to square of velocity was assessed. Similarly the aerodynamic drag in three different tunnel cross-section area (Gyeongbu-HSL: 107 m2, Honam- HSL: 96.7 m2 and Gyeongang Line: 68 m2) was also estimated and compared with that in open air. From the coasting test results, it is found that the aerodynamic drag in tunnel at Gyeongbu-HSL is 24% greater than that in open-section. And it is also noted that the aerodynamic drag in small tunnel (Honam-HSL) is even 38% larger than that in open air. And in the smallest tunnel (Gyeongang Line) the aerodynamic resistance becomes 51% larger. These results explained that the blockage ratio has critical role in the aerodynamic drag increase in tunnel.