Experimental investigation on the influence of drainage structure on vortex tube energy separation

Abstract

The vortex tube is widely used in cooling or heating applications and can also serve as an effective tool for condensing and removing water vapor from natural gas. Experiments were conducted on a counterflow vortex tube equipped with a drainage structure to investigate the underlying energy separation mechanism. This experimental vortex tube features six inlet nozzles and a cold cone with a 2° taper angle. Unlike conventional vortex tubes, the hot end of this design incorporates a drainage channel to expel the separated liquid phase. The inlet pressure varied from 0.1 to 0.4 MPa, and the cold mass fraction ranged from 0.16 to 0.87. Both straight and inclined drainage channels were evaluated and compared. Furthermore, the effect of liquid drainage positions on energy separation performance was examined. The results indicate that under operating conditions of an inlet pressure of 0.4 MPa and a cold mass fraction of 0.38, the maximum temperature drop at the cold end of the vortex tube with an inclined slot drainage structure reached 25 °C, demonstrating superior energy separation performance compared to the straight slot drainage design. This finding suggests that optimizing the drainage structure and position can significantly enhance the energy separation efficiency of the vortex tube. Furthermore, when the drainage structure adopts an inclined groove design and is positioned in the center, the use of the vortex tube for condensing and removing moist air can achieve a maximum removal rate of 77 %, showcasing its tremendous potential in gas treatment applications.