Theoretical Research And Experimental Investigation On Internal Field Of Vortex Tube

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.