The effects of the vortex chamber radius and cold flow ratio on the performance of a vortex tube are studied using R41 gas as the working medium. The standard k-? turbulence model is adopted

where the inlet pressure and temperature were set as 4.0 MPa and 323.15 K

respectively. The cold flow ratio ranges from 0.1 to 0.9

and the vortex chamber radius ranges from 2.5 to 4.5 mm. At a cold flow ratio of 0.4

the tangential velocity first increased and then decreased with the increase in the radial distance of the vortex tube. When the vortex chamber radius was 3.5 mm

the maximum tangential velocity was 159.5 m/s. As the vortex chamber radius increased

the axial velocity of the internal and external swirls decreased. When the vortex chamber radius was 2.5 mm

the maximum axial velocity of the external swirl was 47.6 m/s. The maximum cooling effect was achieved at a flow rate and vortex chamber radius of 1.5 and 0.5 mm

respectively. At a cooling flow ratio of 0.9 and vortex chamber radius of 3.0 mm

the maximum heating effect was 36.3 K. At a cooling flow ratio of 0.6 and vortex chamber radius of 3.0 mm

the maximum cooling capacity and COP were 364.5 W and 0.21

respectively.