均熵流與非均熵流在列車隧道一維空氣動力之分析與影響

The Analysis and Influence of Homentropic and Non-homentropic Flow in 1-D Train Tunnel Flow

黃國倫(Kuo-Lun Hwang)

《中國土木水利工程學刊》 22卷2期 (2010/06) Pp. 179-186

https://doi.org/10.6652/JoCICHE.201006_22(2).0005

摘要

本文應用特徵線法（method of characteristics, MOC）解析列車隧道內一維空氣動力流場，並以試驗結果比對均熵流與非均熵流之分析，及探討均熵流與非均熵流對列車隧道之流速、壓力、阻力、功率與溫度等之影響。無論均熵流或非均熵流分析都可以掌握隧道內之最大壓力；模擬車頭前的壓力結果，非均熵流較均熵流更接近試驗結果，且在車頭與車尾處所遭受的阻力有明顯不同，這有助於更精確的分析列車通過隧道之耗能情況。但壓力波經震盪擾動以後，均熵流或非均熵流分析的壓力震幅較試驗值大，其可能原因將在本文之討論中探討，且有待更進一步的加以研究。

關鍵字

非均熵流 ； 列車隧道 ； 空氣動力 ； 活塞效應

並列摘要

When trains move underground, the layout of tunnel construction will affect the piston effect. Good layout would safeguard tunnel safety, maintain good environment quality and also conserve energy and save the expense of tunnel construction.The piston effect impels the movement of air in the tunnel. The air migration causes drag forces on the train head and tail and friction forces on tunnel walls and train body. Those forces will have two effects on air in tunnels: one is directly to change the air momentum; while the other is to change the air entropy. The change of air entropy would affect the air pressure as well as air density and sonic velocity. That the change of air entropy is taken into consideration in tunnels is called the non-homentropic flow. Otherwise it is called the homentropic flow. Both homentropic and non-homentropic flow will be discussed in this paper.This paper used the Method of Characteristics (MOC) to analysis air dynamic by homentropic or non-homentropic flow in train tunnels.

並列關鍵字

non-homentropic flow ； train tunnel ； air dynamics ； piston effect