CFD investigation of the unsteady airflow and pressure characteristics in the underground highway station with the train passing

Abstract

A numerical research is conducted to clarify the unsteady airflow and pressure characteristics in the full-scale underground highway station to ensure the passenger safety and energy saving in Heating, ventilation and air-conditioning design. Results show pressure characteristics in the tunnel change greatly due to the propagations of compression and expansion waves. The propagations of compression and expansion waves determine the local pressures together. For the first two locations X = −900 m and X = −800 m, the pressure climbs to the peak when the head of the train reaches. However, for the other locations, the pressure is not the maximum when the train reaches, due to the effect of Initial Expansion Wave (IEW). With the raising of train speeds, the positive maximum velocities are increased by 32.60% and 47.58%, respectively. It should be noted that there are two peak values of horizontal velocities successively, with the train speed of 250 km/h and 300 km/h.

Keywords

• underground highway station
• flow field
• pressure characteristics
• tunnel
• train passing
• piston effect