热端管直径对涡流管内部场分布的影响

Effect of Hot-End Tube Diameter on Flow Field of Vortex Tube: A Simulation Study

本文以理想二氧化碳气体为工质,采用Standard k-ε湍流模型,对涡流管能量分离效应进行数值模拟,分析了管内流体速度、温度、压力的分布。在此基础上,探究了进口温度为298.15 K、进口压力为6.5 MPa、冷流率为0.1时,热端管直径对涡流管内速度场、温度场、压力场分布以及能量分离性能的影响。模拟结果表明:热端管直径D在4.0~6.0 mm范围内变化时,随着热端管直径的增大内旋流的轴向、径向空间增大、切向速度逐渐减小、冷热流分界的轴向距离逐渐增大、径向上的压降逐渐减小,并且热端管直径在D=5.0 mm时达到最佳的冷热平衡。

The flow field of ideal CO2 in a vortex tube was empirically approximated,mathematically formulated with standard k-εturbulence model and numerically simulated.The influence of the hot-end tube diameter on the energy separation,distributions of velocity,temperature and pressure was investigated under the conditions:an inlet temperature of 298.15 K,an inlet pressure of 6.5 MPa and a cold flow-rate of 0.1.The simulated results show that the hot-end tube diameter has a major impact.To be specific,as the diameter increases from 4.02 o 6.0 mm,the radial and axial spaces of the internal swirl increase,the tangential velocity decreases,the axial distance of the cold-hot flow boundary increases and the radial distribution of pressure decreases,resulting in an optimized cold-hot balance at a diameter of 5.0 mm.We suggest that the simulated results be of some technological interest for design optimization of vortex tubes.