高海拔地区高速铁路隧道空气动力学特性

为了获得高海拔地区隧道空气动力学效应随海拔高度的变化规律,针对我国中西部及西南部艰险困难山区高海拔低温的气候特点,给出了高速列车进入隧道时产生压缩波的三维可压缩、粘性、非定常流场数值模拟方法,对高速列车进入低气压隧道时产生的气动效应进行研究.研究结果表明:隧道所处海拔高度的变化对隧道内压缩波及隧道出口微气压波的影响较大,随着海拔的升高,大气压的降低会导致隧道内压缩波及隧道出口微气压波的最大值及最小值呈线性降低,降低幅度分别为70%和71%,而大气压的变化对测点压力波形无影响;随着温度的降低,隧道内的压缩波及隧道出口微气压波的最大值及最小值均降低,降低幅度分别为34%和36%,基本呈线性效应;海拔高度的变化对隧道内及隧道外气动效应的影响比温度的大.针对我国高海拔地区的气候特点,根据旅客的舒适度准侧,提出了CRH380B型高寒列车在列车速度为350 km/h、气压为75.99 kPa及气体温度为250 K时的隧道净空断面积约为96 m2,可为下一步高海拔低温条件下高速铁路隧道净空断面积的设计提供参考. 

Aerodynamic Effect Induced by High-Speed Train Entering into Tunnel in High Altitude Area

According to high altitude and low temperature climate conditions of midwestern and southwestern dangerous regions of China, a numerical simulation method of three dimensional compressible, viscous and unsteady compression waves induced by a high-speed train entering a tunnel was presented and aerodynamic effect also be studied.The results show that the range of the tunnel altitude has a profound effect on compression waves inside the tunel and micro-pressure waves at the tunnel exit. With the increase of altitude, the decrease of atmospheric pressure will cause a linear decrease of maximum and minimum value of compression waves and micro-pressure waves by 34% and 36% respectively, and has little influence on wave forms at measuring points.Besides, as temperature decreasing, the maximum and minimum value of compression waves and micro-pressure waves decrease linearly by 34% and 36% respectively.According to comparison, it assumes that altitude plays a much larger role in aerodynamic effect outside or inside the tunnel than temperature. At last, according to high altitude climate conditions of China and the principle that aims to make passengers comfortable, it provides that the tunnel area is 96 m2 when the CRH380B train runs at 350 km/h, 75.99 kPa and 250 K. This suggestion provides a guidance for sectional area designing of high-speed railway tunnel in high altitude and low temperature conditions.