Feasibility Analysis of Natural Ventilation and Airflow Characteristics for Diesel-Hauled Train Pollutants in High-Altitude
Tunnels

ZHENG Jiayu; SUN Sanxiang; TIAN Weihai

doi:10.3973/j.issn.2096-4498.2024.S2.029

2024 , Vol. 44 >Issue S2: 300 - 308

DOI: https://doi.org/10.3973/j.issn.2096-4498.2024.S2.029

Feasibility Analysis of Natural Ventilation and Airflow Characteristics for Diesel-Hauled Train Pollutants in High-Altitude Tunnels

ZHENG Jiayu ,
SUN Sanxiang ,
TIAN Weihai

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(1. School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, Gansu, China; 2. Engineering Research Center of Comprehensive Utilization of Water Resources in Cold and Arid Regions, the Ministry of Education, Lanzhou Jiaotong University, Lanzhou 730070, Gansu, China; 3. Gansu Provincial Laboratory of Rail Transit Mechanics Application, Lanzhou Jiaotong University, Lanzhou 730070, Gansu, China)

Online published: 2024-12-20

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Abstract

There is no numerical simulation and theoretical data support for diffusion patterns of pollutants in high-altitude railway tunnels during operation period. Thus, the diesel-hauled train pollutants ventilated by nature wind using piston wind in high-altitude tunnels is numerically simulated. A three-dimensional model of a high-altitude single-tube single-track railway tunnel is established using CFD software. The CO emissions from diesel locomotives is taken as the characteristic pollutant, and based on simulation results under different natural wind speeds and conditions, the impact of external natural wind speed and direction on pollutant diffusion, the attenuation characteristics of piston wind, and the spatiotemporal variation of CO concentration are quantitatively analyzed. These provide a theoretical support for the design of operational ventilation in high-altitude tunnels, ensuring the safety, effectiveness, and scientific rigor of the ventilation scheme. The results indicate that: (1) The diffusion of pollutants from a diesel-hauled train follows an exponential decay pattern. (2) Under positive wind speed, the CO attenuation distance decreases with increasing wind speed; whereas it increases with increasing wind speed under reverse wind speed. (3) Under a wind speed of over 3 m/s, the concentration of pollutants in the tunnel typically remains below 30×10^-6, regardless of wind direction; under a wind speed of 2 m/s, a 4 km long high-altitude tunnel can achieve air replacement within 20 min using piston wind, ensuring that the air quality meets safety standards.

Key words： high altitude; natural ventilation; operational ventilation; pollutant dispersion; railway tunnel; diesel-hauled trains; airflow characteristics

Cite this article

ZHENG Jiayu , SUN Sanxiang , TIAN Weihai .

Feasibility Analysis of Natural Ventilation and Airflow Characteristics for Diesel-Hauled Train Pollutants in High-Altitude Tunnels

[J]. Tunnel Construction, 2024 , 44(S2) : 300 -308 . DOI: 10.3973/j.issn.2096-4498.2024.S2.029

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