摘要
基于粘性流体k-ε双方程湍流模型,建立真空管道交通系统三维数学模型和物理模型,并在超音速状态下对所建模型进行数值模拟。超音速时,气流流经车体形成熵层,根据熵层分布规律进一步分析系统内能量的传递及气动热的生成。结果表明:最大熵值出现在车头和车尾的鼻尖处,生成的气动热最多,该处混乱程度强,能量传递多,在车头形成气动热并在车尾积聚;熵层在车头处环状分布,车身处环车身轮廓分布,但车身后半段车体下方区域出现了小范围的低熵熵层;在后车肩截面处,车体周围的熵层呈"帽"状分布,熵值较周围降低,这部分熵层中的流速变化大,热量传递快,原有的稳定性被破坏。根据熵层的分布规律可以发现,车头部位温度较低,由车头至车尾温度逐渐升高,车尾车肩处温度达到最高。
The evacuated tube transport（ETl＇）was physically modeled in 3-dimension, based on the k-ε two-equation turbulence model, and numerically simulated. At a supersonic speed, the entropy layer forms while air flows along the train＇s body;the energy transfer and pneumatic heat generation can be evaluated by analyzing the entropy layer distribution. The simulated results show that the entropy and aerodynamic heat generated maximize at beth apexes of the train＇ s head and tail, accompanied by the strongest chaos and most energy transfer. The non-symmetric, radial entropy distribution significantly depends on the horizontal position of the air/train interface. For example, circular contours at the head and contours resembling the body＇s cross-section in the middle. As the airflows to its latter half, a small range of low entropy layer forms at the bottom area; and above the tails＇ s houlder and around the body, the entropy layers hows a ＂hat-shaped＂ distribution with the entropy lower than that of neighboring area, and where rapid changes in air flow rate, large amount of heat transfer, and destruction of the original stability emerge. We concluded that the temperature increases from head to tail, peaking at the shoulder of its tail.
出处
《真空科学与技术学报》
EI
CAS
CSCD
北大核心
2014年第8期775-780,共6页
Chinese Journal of Vacuum Science and Technology
关键词
真空管道交通
马赫数
熵层
阻塞比
Evacuated tube transportation, Mach number, Entropy layer, Blockage ratio
