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

Nomenclature

PSD	=	Platform screen door
VT	=	velocity transducer
PT	=	pressure transducer
D	=	Distance away from the entrance of the tunnel, m
1-8	=	pressure, Pa
a, c, e, g	=	when the head of the train arrives the measure point
b, d, f, h	=	when the tail of the train arrives the measure point
n	=	the Initial Compress Wave propagates to the measure point
ICW	=	Initial Compress Wave, Pa
IEW	=	Initial Expansion Wave, Pa

Acknowledgments

This study is supported by National Natural Science Foundation of China (Grant No. 51706189).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Key Research and Development Program of China [2018YFC0705000].

Notes on contributors

Yongliang Xie

Yongliang Xie is an assistant professor of Southwest University, Chengdu, China. He is engaged in the safety issue in the renewable energy system and transportation.

Qizhang Li

Qizhang Li is graduating from Southwest University, Chengdu, China. He obtained his Master's degree in Engineering in 2021. His research interest is tunnel ventilation.

Fujian Jiang

Fujian Jiang is an assistant research fellow of Southwest University, Chengdu, China. His major research field is the wind and thermal environment of the building.