vortex tube, energy separation, refrigerants
Vortex tube is a simple energy separation device, also known as Ranque tube or Hilsch tube, which can separate a high-pressure stream into two different hot and cold streams. Since its simple structure and unique temperature separation characteristics, vortex tube has been widely used in various industries. In recent years, with the in-depth study of the vortex tube, it has been found that compared with the conventional expansion expander and the throttle valve, the vortex tube is much more structurally simple and efficient, respectively. Researchers have proposed the use of the vortex tube in the refrigeration system in order to reduce the throttling loss and improve system efficiency. This has important implications for improving the performance of the system, to achieve energy saving and emission reduction. However, due to the different physical properties of the different working fluid, energy separation in the vortex tube are not the same. In the existing studies on the vortex tube, the working fluid mainly used air, nitrogen, carbon dioxide and other natural refrigerants, the research about the influence of refrigerants is few. Due to the fact that the vortex tube is increasingly used in refrigeration and heating system, it is urgent to study the coupling characteristics between vortex tube and refrigerants and find optimal conditions in different systems. The different temperature separation effect of the refrigerants in the vortex tube in the low inlet pressure(300kPa) have been studied in our previous study and three fluid characteristics (specific heat ratio, kinematic viscosity, thermal conductivity) were considered as main influencing factors of energy separation. The influence of different working fluid in high pressure conditions has not been considered ,which is part of research work in this paper. The coupling characteristic between vortex tube and refrigerants wais studied and the closed loop system was constructed. R134a, R744, R32, R227ea were selected as the working fluids, experiments were carried out in different inlet pressure(500kPa?850kPa), different inlet temperature (308.15K?333.15K), different cold flow ratio (20%?97%). The temperature separation of different working fluids under different conditions were explored and the influences of different characteristics of the working fluids on the temperature separation process were discussed. These studies can help more profound understanding of the vortex tube temperature separation process, and also has certain significance on the applications of the vortex tube in the refrigeration system.