Airflow in a Subway Station due to Train Transit. Numerical Analysis and Comparisons with Measurement Results.

Abstract

In this work, the airflow generated by several types of winds in a subway station is numerically simulated by the two-dimensional SIMPLE method. A steady wind, an unsteady wind and a wind created by movement of actual train, which are the inflow or outflow conditions in the tunnel of the station, are treated for evaluation of the steady or unsteady effects of airflow in the station and estimation of the accuracy of this analysis. The subway station model used in this analysis consists of a simplified configuration of a platform, a baffle at the front end of the platform and four tunnels. In the case of the steady inflow, the airflow circulates around the platform behind the baffle. In the case of the unsteady inflow, this circulating flow gradually extends with time from the front end of the platform to the center. However, this circulating flow does not appear in either case of the steady and the unsteady outflow. In the case of the actual train wind, the calculated velocity of time process agree well with the results of fieldwork tests in the tunnels and on the platform. This numerical analysis, therefore, can be used to evaluate the airflow in an actual subway station with an intricate configuration including for example staircases and a ventilation system.