Effect of operational modes on the train-induced airflow and thermal environment in a subway station with full-height platform bailout doors

摘要

Train-induced unsteady airflow (TIUA) has a considerable effect on the ventilation and thermal environment of a subway system. Because of the complexity of a subway ventilation network and the variability of train activity, analytical and numerical methods are limited in reflecting the actual situation. In this study, a field test on the TIUA and air temperature in a subway station with full-height platform bailout doors (PBDs) was conducted under four operational conditions. The results showed that the train running parameters and operational modes, including the piston vent shafts, bypass ducts and cotton curtains at the entrances, had substantial effects on the TIUA and thermal environment. The air inflow and outflow rates through the entrances increased by 20.99% and 39.66%, respectively, as the train interval decreased by 104 s (case 2). Moreover, there was a greater difference in the air inflow rate through the entrances under different operational modes. Furthermore, uninstalling the cotton curtains increased the air inflow and outflow rates by 2.09- and 1.36-fold, respectively, at a train interval of 510 s (when comparing case 1 and case 2). In addition, removing the cotton curtains, the maximum decreases in air temperature in the entrances, hall, and platform were approximately 5.10 ?C, 4.85 ?C, and 1.39 ?C, respectively, and the thermal environment with the single open system and closed bypass ducts condition might be better than that with the internal circulation system and open bypass ducts condition. This study provides first-hand data for ascertaining the characteristics of the TIUA and optimizing subway operational modes.