三维数值模拟冷孔板孔径对涡流管能量分离特性的影响

以理想CO₂气体为工质, 采用Standard k-ε湍流模型对涡流管冷热分离效应进行数值模拟。通过分析管内工质流动状态和温度、压力的分布, 发现:CO₂气体在内层强制涡区与外层自由涡区不断的进行热质交换, 促进涡流管发生能量分离。在此基础上, 探究进口温度为298.15 K、进口压力为6.5 MPa, 冷流比在0.3~0.9范围变化时, 冷孔板孔径对涡流管制冷制热性能的影响, 模拟结果发现:冷孔板孔径在1.7~2.62 mm范围内变化时, 随着冷孔板孔径的增大, 涡流管的制冷效应和制热效应逐渐增大, 且当冷孔板孔径为2.62 mm时, 涡流管获得最大总温差36.83 K。

Influence of Cold Orifice Diameter on Energy Separation Characteristics of Vortex Tube: A Simulation Study

The flow field of CO₂ gas in a vortex tube was mathematically formulated with standard k-ε turbulence model, theoretically analyzed and numerically simulated with software CFD. The impact of the known variables, including the temperature and pressure at the input, cold mass ratio and cold orifice diameter, on the cooling/heating of the vortex tube was investigated. The simulated results show that a continuous CO₂ heat/mass exchange between the inner forced-vortex and outer free-vortex zones explains the energy separation of the vortex tube; and that the cold orifice diameter significantly affects the cooling/heating. For example, as the cold orifice diameter increases from 1. 7 to 2. 62 mm, the temperature difference increases because of the cooling/heating. With a diameter of 2. 62 mm and a cold mass ratio of 0. 9, the temperature difference of the vortex tube is 36. 83 K.