Experimental investigation of COP and CMF values of a vortex tube using generators with different parameters

Vortex tubes, referred to as Ranque-Hilsch tubes, are used as a local cooling/heating system today because they don't harm the environment, don't require any chemicals when separating into hot and cold fluids, are simple in structure and don't have moving parts. With the help of the compressor, pressurized air enters the vortex through the entrance lule to the tube. Compressed air entering the vortex tube creates a vortex by hitting the vortex generator. The compressed air, that rotates and progresses in the vortex tube, is separated into hot and cold fluids at the stopping point in the tube due to the effect of different angular velocities caused by the effect of friction in the tube center and the walls. The hot fluid comes out of the holes of the control valve located on the hot end side of the tube. On the other hand, cold air passes through the middle of the vortex generator and exits the cold outlet diameter (d2) and leaves the tube. Thus, fluids with two different outlet temperature values were obtained in the vortex tube. In the experimental study, air was used at 5 bar pressure and 40 m3/h flow rate. In the experiments, vortex generators with three different nozzles (n=4,5,6) and three different hot fluid output internal diameters (d1=5,7,9 mm) were used. The cold mass fraction (CMF) was changed by changing the control valve gaps on the hot outlet side of the vortex tube. The effect of this ratio on cooling performance has been investigated experimentally. Since the changing CMF value changes the amount of air coming out of the hot and cold side, the outlet temperature difference (∆T) of the hot and cold fluid has also changed depending on this ratio. It has been observed that the cooling performance coefficient (COP) of the vortex tube changes with the change of CMF. The geometric parameters of the vortex generator directly affected the cooling performance of the vortex tube. In order to examine the cooling performance of the vortex tube, the experiments were carried out for vortex generators with 9 different geometric parameters. As a result of experimental studies, it was observed that vortex tube cooling performance (COP) for different d1 and CMF values varies between 0,1 and 1,3. The maximum COP value was obtained as 1,27 at d1=9 mm, CMF=0,85 and n=6. The maximum ΔT value obtained among the vortex generators with n=4,5,6 nozzle numbers and different hot fluid outlet diameters was obtained as 52,9 ºC at d1=9 mm, CMF=0,85 and n=5.