为解决高海拔铁路隧道在运营期间污染物扩散规律缺乏数值模拟及理论数据支撑的问题，对内燃牵引高海拔隧道利用活塞风实现自然通风的可行性进行模拟分析。基于CFD软件建立高海拔单洞单线铁路隧道三维模型，以内燃机车排放的CO为特征污染物，基于不同自然风风速和风向条件下质量分数场模拟结果，定量分析外界自然风风速和风向对污染物扩散的影响，活塞风衰减特性和CO质量分数的时空变化规律，进而为高海拔隧道的运营通风设计提供理论支持，确保通风方案的安全性、有效性和科学性。结果表明： 1）内燃牵引列车尾部污染物扩散呈指数衰减规律。2）正向风速下CO衰减距离随风速增大而减小，反向风速则随风速增大而增大。3）在风速>3 m/s时,不论风向，隧道内污染气体聚集质量分数通常都在30×１０－６以下；在风速为2 m/s时，长度为4 km的高海拔隧道利用活塞风可在20 min内完成空气置换，确保空气质量达到安全标准。
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.
