Field study of the effect of piston wind on the airflows at the controllable vents and exits of a subway station

Knowing the distribution of piston air flow at the controllable vents and exits can help to utilize the piston wind more effectively. Field test data were collected to analyse the air velocity distribution at the controllable vents and the ventilation volume of the station. The results showed that variations in the air velocity at the controllable vents within a cycle could be divided into four stages and that the air velocities in the third and fourth stages were high. The air velocity distributions at the controllable vents were uneven, showing a rapidly decreasing trend along the length of the platform. The air velocities at the controllable vents located at the front and the end of the platform were more than 3 m/s and less than 0.1 m/s, respectively. The ventilation volumes under Mode 1 (the controllable vents on one side of the platform are open) and Mode 2 (the controllable vents on both sides of the platform are open) were 89128 m 3 /h and 56488 m 3 /h, respectively. The ventilation volume under Mode 2 did not satisfy the ventilation volume requirement of the station. Therefore, opening the controllable vents on only one side of the platform is recommended. • Variations in the air velocity at the controllable vents within a cycle could be divided into four stages. • The air velocity distributions at the controllable vents showed a rapidly decreasing trend along the length of the platform. • The ventilation volume under Mode 2 did not satisfy the ventilation volume requirement of the station. • Opening the controllable vents on only one side of the platform is recommended.