隧道中捷運軌道車輛移動之流場模擬

Abstract

在現代捷運設計中在地下站台內加裝了月台門，為了模擬加裝此設備後因活塞效應而在車頭及月台門上產生的壓力，我們在月台的正上方設置可直通大氣的釋壓井以及兩隧道間的旁通釋壓閥以疏解壓力；本文利用了套裝軟體STAR-CD作為進行模擬的工具，並以速度、列車於單向或雙向軌道通行及有無開放旁通釋壓閥等參數進行了五個案例的模擬分析，發現流場會在列車通過釋壓設備時產生壓力波峰值，而列車以時速40、65及80公里在雙向軌道通車過站時其壓力極值分別為501.8、1549及2006 Pa；同時我們也利用改變釋壓井設計參數的不同來對照比較其對於流場壓力極值的影響，並找出壓截面積大小及設置的相對位置旁通釋壓閥的有無對於流場壓力極值的影響，以期能找出最佳設計來將流場中壓力極值降到最低。

Now the new design of underground station is required to build a doorway between the platform and railway. In order to release the pressure rise, generated due to piston effect by the moving trains on the two tracks in the underground, it designs to have the ventilation shaft, connected to the tunnel and penetrated upright into the ground atmosphere, and the bypass damper between two tracks. The commercial software STAR-CD is utilized as a simulation tool. The varying parameters are the trains’ velocity, the train operating on single or both tracks and the installation of bypass damper or not. There are 5 case studies taken into consideration. It is found that there would have the occurrences of pressure peak as the trains pass through the ventilation apparatuses. The highest pressure values in the flow field during the train operating on both tracks at velocities of 40, 65 and 80km/r are 501.8, 1549 and 2006 Pa, respectively. The corresponding occurring spots are all the same. The volume flow rates in the ventilation apparatuses are proportional to the trains’ velocity. From the predicted results, it shows that the cross-sectional area and the relative position of the ventilation apparatus have a great influence on the pressure release. Finally, this study finds that the establishment of bypass damper seems not to work well on the pressure release. If having no other purpose, it is suggested to remove it.