Train-induced unsteady airflow effect analysis on a subway station using field experiments and numerical modelling

Abstract

In recent years, subway systems (rail transit) have become an increasingly significant means of urban transportation. Platform screen doors (PSDs) can play an important role in enhancing the thermal environment in subway stations. However, train-induced unsteady airflow results in unorganised ventilation at the entrances (supplying fresh air and causing heat exchange) and air infiltration at the PSDs (causing heat exchange) in subway stations with PSDs. In the present study, field experiments (in Xi'an, China) and numerical modelling were conducted to investigate the rate of air inflow at the entrances and the PSDs of subways. The accuracy of the model was verified using the results from field experiments. In addition, the effects of various factors such as the traffic density, the piston vent shaft at the station downstream location (PVSASDL), and the season were analysed. The simulation results showed that turning on the PVSASDL could reduce the rate of air inflow at the entrances to 29.2–93.8%, while that at the PSDs could be enhanced to 121.8–126.3% under different traffic densities. In addition, to explore appropriate control of the PVSASDL in winter, different outdoor temperatures were simulated for a traffic density of 12 pairs/hour. It was found that the temperature in the station could meet the standard requirements when outdoor temperatures were greater higher than −5 °C with either open or closed PVSASDL conditions.