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Sun S.,Lanzhou Jiaotong University | Sun S.,Engineering Research Center for Cold and Arid Regions Water Resource Comprehensive Utilization of Ministry of Education | Zhang Y.,Lanzhou Jiaotong University | Lei P.,Lanzhou Jiaotong University | And 2 more authors.
Zhongguo Tiedao Kexue/China Railway Science | Year: 2015

Field monitoring was carried through on the concentration of CO and NOx (converted to NO2) and air speed during normal operation under diesel locomotive traction condition in the First Guanjiao Tunnel (mountain-valley type) and Yangbajing 1# Tunnel (river-valley type), both 3 000 m above sea-level and with the length of more than 3 km. With theoretical analysis and one-dimensional numerical simulation method, the diffusion coefficients of pollutants and the natural ventilation threshold for single-track railway tunnel at high altitude under diesel locomotive traction were studied. The results show that, the diffusion coefficients of CO and NOx in single-track railway tunnel at high altitude under diesel locomotive traction have a quadratic parabola relationship with air speed and are far greater than those in plain area. The one-dimensional flow diffusion equation of instantaneous point source can reasonably describe the diffusion rule of pollutants in single-track railway tunnel at high altitude. For single-track railway tunnel at high altitude with the length less than 4 km, when the running speed of diesel locomotive is over 48 km·h-1 and the natural air speed is 1.5~2.0 m·s-1, natural ventilation can be realized in the tunnel. © 2015, Chinese Academy of Railway Sciences. All right reserved.

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