Study On The Influence Of Intake Parameters On The Refrigeration Performance And Flow Field Characteristics Of Vortex Tube

Vortex tube is a kind of energy separation device with strong applicability,which is used to separate high pressure gas into low pressure gas with different temperature.Because of its simple structure,no internal heat source,convenient operation,safe and reliable,vortex tube is often used in many fields such as industrial processing cooling,oil separation and so on.Although the structure of the vortex tube is relatively simple,its internal fluid flow characteristics are very complex.It is of great significance to further reveal the energy separation mechanism of the vortex tube to study the fluid flow characteristics in the vortex tube.In this paper,using the method of numerical simulation and experiment,using compressed air as the working fluid,by changing the inlet temperature,cold flow rate and inlet pressure of the vortex tube,the variation rules of the cooling performance,temperature field and velocity field of the vortex tube under different working parameters are obtained,and the energy separation mechanism is summarized and analyzed.The concrete conclusions are as follows:From the refrigeration performance point of view: at the same cooling flow rate,the increase of inlet temperature or inlet pressure will increase the influence on the cooling temperature effect and unit cooling capacity of vortex tube,but the influence of inlet pressure on the temperature difference between hot end and cold end is greater than that of inlet temperature.The inlet temperature has no effect on the cooling efficiency of the vortex tube,but increasing the inlet pressure will reduce the cooling efficiency.There is an optimal cooling flow rate to maximize the cooling performance of the vortex tube,and the optimal cooling flow rate is not affected by the operating parameters.From the point of view of energy separation: increasing the inlet temperature and increasing the inlet pressure can promote the energy separation effect in the vortex tube.The closer the fluid is to the outlet of the hot end,the smaller the influence of the inlet pressure on the energy separation process of the fluid in the tube.The energy separation effect of vortex tube does not increase continuously with the increase of cooling flow rate,but increases first and then decreases.From the perspective of temperature distribution: with the increase of cold flow rate,the cold flow region in the vortex tube gradually decreases,and the average temperature in the cold flow region increases.At the same cooling flow rate,increasing inlet temperature or inlet pressure can increase the range of inlet temperature isothermal surface,but the influence of inlet pressure on the isothermal surface is more obvious.From the perspective of velocity distribution,the velocity field of vortex tube decreases with the increase of cooling flow rate.There is a relative static surface of axial velocity in vortex tube,and its range increases with the increase of cooling flow rate.Among the threedimensional air velocity in the vortex tube,the circumferential velocity is most affected by the cooling flow rate,and the radial velocity is the least affected by the cooling flow rate.The range of relative stationary surface of vortex tube increases with increasing inlet temperature or inlet pressure.