The influence of working gas characteristics on energy separation of vortex tube

Currently, little research has been done regarding the influence of working gases, especially HFCs, on energy separation in vortex tubes. Based on this, a vortex tube performance test device was designed, R728, R744, R32, R22, R161, R134a were selected as working fluids. The inlet pressure of the vortex tube was changed from 0.2 MPa to 1.3 MPa (abs), and the inlet temperature was adjusted to about 12 °C. The performances of the vortex tube with different working fluids were tested. It was found that the temperature separation and outlet pressure increased with the rise of inlet pressure for R728 and R744, but there was an extreme value for R744 when the inlet pressure reached about 1.1 MPa (i.e. when the temperature reached a peak point of about 15 °C), and three fluid characteristics (specific heat ratio, kinematic viscosity, thermal conductivity) were considered as main influencing factors of energy separation. The isenthalpic throttling effect of the working fluids also influenced the cooling effect of the vortex tube. In addition, the wall temperatures of the vortex tube hot end were measured; the phenomena of the cold end of the vortex tube were observed; and the conditions for the liquefying phenomena using HFCs were evaluated.