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| 涡流管流场结构及能量分离性能的LDV实验研究 |
| Experimental investigation of flow structure and energy separation performance of Ranque–Hilsch vortex tube with LDV measurement |
| 投稿时间：2019-04-08 修订日期：2019-05-20 |
| DOI： |
| 中文关键词: 涡流管 LDV 流动结构 能量分离性能 折返流边界 |
| 英文关键词: Ranque–Hilsch vortex tube LDV flow structure energy separation performance reverse flow boundary |
| 基金项目:基于流场非定常特性和流动结构分析的涡流管能量分离机理及其优化准则研究 |
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| 中文摘要: |
| 本文设计了直径为30mm的可组装式透明涡流管以实现主流道可视化，并采用二维激光多普勒测速技术得到子午面时均流场。研究了不同冷流比(0.1-0.9)、主流道长度(360 mm、600 mm、900 mm和1200 mm)、入口压力(0.1 bar、0.2 bar)下的轴向速度和径向速度分布，特别是折返流边界分布情况，及其对能量分离性能的影响。LDV结果表明，时均轴向速度分布具有较好的轴对称性，不同压力下流动结构具有相似性，径向速度大小远小于轴向速度。增加冷流比会导致折返流边界径向膨胀，并揭示了在过短管和过长管中两种能量分离恶化机制——过短管中折返流面过厚、在过长管中轴向滞止点向冷端靠拢。该结果验证了以往所提出的优化准则，同时可以说明滞止点并不是涡流管主流道中的一种基本流动结构。 |
| 英文摘要: |
| In this study, diameter of 30 mm transparent vortex tubes were designed for the main tube visualisation and a 2D laser Doppler velocimetry (LDV) measurement was adopted to investigate the time-averaged flow field on the meridian plane. Various operation conditions with different cold mass fractions (0.1–0.9), tube lengths (360mm, 600mm, 900mm and 1200mm), and inlet pressures (0.1bar and 0.2bar) were studied to obtain the distributions of the axial and radial velocities and to reveal how the reverse flow boundary affects the energy separation performance, particularly. The LDV results show that the time-averaged axial velocity distribution present good axial symmetry, and the flow structure present similarity under different pressure. Radial velocity is far less than the axial velocity. Increasing cold mass fraction leads to the radial expansion of reverse flow boundary. Two deterioration models in the energy separation performance of an excessively short or long tube were revealed: the over thick reverse flow boundary in the short tube, and the movement of the stagnation point toward to the cold end in the long tube. The proposed tube optimization criteria were proven. Meanwhile, it also shows that stagnation point is not a basic flow structure inside vortex tube. |
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