The increased operating speed of metro trains exacerbates aerodynamic effects in tunnels. Insufficient sealing performance of the metro train allows alternating pressure waves to propagate into the carriages, disrupting interior airflow distribution and adversely impacting passenger comfort. In this paper, pressure fluctuations and longitudinal wind speed variations in the carriage were investigated by field tests. The effects of the ventilation shaft and the operational status of fresh air valves on the interior and exterior flow fields of the metro train were analyzed. The results indicate that the ventilation shaft is a primary factor inducing rapid pressure fluctuations inside and outside the metro train. When the train stops at a station, the dynamic opening and closing of doors can generate transient pressure fluctuations in the carriage, with a pressure differential of 166.83 Pa. During metro train operation, the longitudinal wind speed exhibits a significant non-uniform distribution, and the wind speed curve resembles a “U-shape”. The maximum characteristic wind speed is observed in the seventh carriage, reaching 1.76 m/s. Furthermore, closing the fresh air valves significantly improves the sealing performance of the metro train. The interior pressure variation amplitude decreases by 37.71% during the opening and closing of doors. The reduction in peak-to-peak interior pressure ranges from 52.91% to 66.63%, while the maximum longitudinal characteristic wind speed decreases to 0.22 m/s. These findings provide engineering guidance for optimizing the air conditioning system and improving passenger comfort.
Feng et al. (Mon,) studied this question.