The evacuated tube transportation has great potential in the future because of its advantages of energy saving and environmental protection. The train runs in the closed tube at ultra-high speed. The heat quantity generated by aerodynamic heating is not easy to spread to external environment and then accumulates in the tube, inducing the ambient temperature in the tube to rise gradually. In this paper, a three-dimensional geometric model and the Shear Stress Transport (SST) κ-ω turbulence model are used to study the influence of initial ambient temperature on the structure of the flow field in the tube. Simulation results show that when the train runs at transonic speed, the supersonic flow region with low temperature and low-pressure is produced in the wake. The structure of the flow field of the wake will change with the initial ambient temperature. And the higher the initial ambient temperature is, the shorter the low temperature region in the wake will be. The larger temperature difference caused by the low temperature region may increase the temperature stress of the tube and affect the equipment inside the tube. Consequently, the temperature inside the tube can be maintained at a reasonable value to reduce the influence of the low temperature region in the wake on the system.

中文翻译：

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初始环境温度对管道系统中空气动力加热影响的数值研究

真空管运输由于其节能环保的优点，在未来具有巨大的潜力。火车在封闭的管道中以超高速运行。由空气动力学加热产生的热量不容易散布到外部环境中，然后在管中积聚，从而导致管中的环境温度逐渐升高。本文使用三维几何模型和剪切应力传递（SST）κ-ω湍流模型来研究初始环境温度对管内流场结构的影响。仿真结果表明，当列车以跨音速行驶时，在尾流中会产生具有低温，低压的超音速流动区域。尾流流场的结构将随初始环境温度而变化。初始环境温度越高，尾流中的低温区域越短。低温区域引起的较大温差可能会增加管子的温度应力，并影响管子内部的设备。因此，可以将管内部的温度维持在合理的值，以减小尾流中的低温区域对系统的影响。