CFD Analysis of Airflow Organization in the Public Area of Island Platform Subway Station
Yanqin ZHANG, Tong LIN, Shiji CAO, Chenxu ZHAO, Jiaobao LIIntroduction/Objective:
This study investigates the airflow organization in the public area of an island-platform subway station and evaluates the effect of air-supply-ratio adjustment on airflow uniformity.
Methods:
A three-dimensional CFD model was established for the station hall and platform public areas. Seasonal boundary conditions were determined according to the operating modes of the ventilation and air-conditioning system. The SST k–ω turbulence model was used to simulate the velocity fields under typical seasonal conditions.
Results:
Under summer conditions, the area-averaged occupied-zone velocities of the station hall and platform levels were 0.34 m/s and 0.39 m/s, respectively, both lower than the summer limit of 0.5 m/s. However, high-velocity regions were observed near the supply air outlets. After adjusting the air-supply ratio, the average velocities decreased to 0.30 m/s and 0.35 m/s, corresponding to reductions of 11.8% and 10.3%, respectively.
discussion:
The results indicate that the summer operating condition is the most critical for airflow organization in the studied station. The side-supply/side-return configuration and the interaction between multiple air supply ducts caused locally high velocities and uneven airflow distribution, which may reduce passenger comfort and lead to unnecessary energy consumption. By redistributing the air supply ratio between ducts, the ventilation performance in the public area was improved without increasing the total air supply volume, demonstrating that duct air distribution optimization is an effective and practical energy-saving measure for subway stations.
Discussion:
The main airflow problem under summer conditions was not overall velocity-limit exceedance, but local airflow non-uniformity near the supply air outlets. Adjusting the air-supply ratio improved the airflow distribution in the occupied zone.
Conclusion:
Air-supply-ratio adjustment can improve airflow uniformity in the public area of an island-platform subway station under unchanged total air-supply volume, providing a reference for ventilation operation optimization.