【作者】 闫立春；

【导师】 宋福元；

【作者基本信息】 哈尔滨工程大学 ， 工程热物理， 2008， 硕士

【摘要】 涡流管是一种没有运动部件的简单的能量分离装置,它能够将高压气流分离成温度不同的低压冷热气流。由于它具有操作方便、运行可靠、免维护等一系列优点和制冷、制热、空调以及混合物的分离等多方面功能,在科学研究及工业等诸多领域得到愈来愈广泛的应用。涡流管几何结构虽然简单,其中发生的能量分离过程却非常复杂,所以,关于涡流管能量分离效应的研究一直是许多研究者研究的焦点。本文利用热力学第一定律得到了涡流管制冷效应、制热效应及冷流比之间的关系式。另外,分析了柱坐标系下可压缩流体湍流运动总能量方程,通过分析发现,涡流管内发生的能量分离效应主要是由径向湍流脉动引起的热流通量、湍流轴向剪切应力功和湍流切向剪切应力功引起的。将涡流管类比成热交换器,建立理论分析模型,得到了冷流比等参数和能量分离效应的函数关系式,分析了这些参数对能量分离效应的影响规律。结果表明:冷流比、入口温度、入口压力及无量纲参数对涡流管的制冷、制热效应有着极其重要的影响。自行设计了涡流管特性研究实验台,对涡流管内部温度场进行了测试,详细研究了冷流比这一特定因素对涡流管内温度沿径向和轴向分布的影响。研究结果表明:所研制的测温热电偶能够满足实验要求,实验结果很好地反映涡流管内温度场分布规律,为涡流管能量分离机理今后的研究提供参考。将涡流管几何模型简化为二维轴对称模型,利用流体力学软件对涡流管内的能量分离过程和流动特性进行数值模拟。研究了不同入口压力和冷流比对涡流管内不同径向位置处的总压、静压、总速、切速、轴速和温度等各个参数沿径向分布的影响规律,研究结果表明:入口压力和冷流比对涡流管的能量分离效应有着重要的影响。这些结论为涡流管的设计和应用奠定了基础。更多还原

【Abstract】 The vortex tube is a simple device with no moving parts that is capable of separating a high-pressure flow into two lower pressure flows of different temperatures. Due to simple structure, convenient maintenance, reliable run and so on, the vortex tube has been found increased use in commercial application, such as cooling, heating, air conditioning and separating gas mixtures, which is highly reliable, and is easy to regulate and to obtain energy flows with parameters that vary within very wide limits. The vortex tube has extraordinary widespread prospect in the applications of scientific researches and industrial domain. Despite the simplicity of the vortex tube’s geometry, the energy separation phenomenon is quite complex. So the vortex tube and theoretical value of coherent energy separation have been being focused by many researchers.Relational expressions among cooling effect, heating effect as well as cold mass fraction were obtained by the thermodynamic first law. The energy separation effect inside the vortex tube was disclosed through analyzing turbulent total energy equation of compressed air under the conditions of cylindrical coordinate. The energy separation effect caused by compressible swirl air inside the vortex tube is mainly due to radial heat flux, viscous shear work in the axial and tangential direction.A new theoretical analysis model was established to understand the mechanism of the energy separation effect with the cold mass flow fraction and so on in a vortex tube by analogizing it as a heat exchanger. These parameters compared with the energy separation effect function relationship were obtained. The cold air fraction to influence rule of the energy separation effect was analyzed. The result indicated: The cold air fraction, the inlet temperature, the inlet pressure and the non-dimensional parameter M to cooling effect, heating effect had the extremely important influence.An experimental apparatus is specially designed and amounted for the purpose of testing the performance of temperature field in a vortex tube. The influences of cold air fraction on the distributions of various flow parameters along different axial and radial directions were investigated. The results show that the bare thermocouples can meet the experimental requirements very well, the temperature profiles from experiments are shown to agree accurately with the previous studies, which provide a credible means for further study on the mechanisms of the energy separation inside the vortex tube.A two-dismensional axi-symmetric CFD model has been developed that exhibits the general behavior expected from a vortex tube. The influences of inlet pressure and cold air fraction on the distributions of total pressure, static pressure, total velocity, tangential velocity, axial velocity and temperature at different radial location various were investigated. The results show: The inlet pressure and the cold flow fraction had the important influence to the vortex tube energy separation effect. These conclusions provided the foundation for designing and applicating of the vortex tube.更多还原