Exergy analysis of a counter flow Ranque–Hilsch vortex tube for different cold orifice diameters, L/D ratios and exit valve angles

An experimental investigation is made to find out the effects of the cold end orifice diameters, length to diameter ratio and exit valve angles on the heating and cooling performance of the counter flow Ranque–Hilsch vortex tube with air as a working fluid. The tube and cold end orifices used at these experiments are made of brass. Three cold end orifices (5, 6 and 7 mm) have been manufactured and are used five different L/D ratios (15 plain tube, 15–18 with 4° divergence angle) and exit valve angles (30°–90°). Inlet pressures were adjusted from 200 to 600 kPa with 100 kPa increments, and the exergy loss, exergy efficiency was determined. As a result of the experimental study, it is determined that the exergy loss between the hot and cold fluid is decreased with increasing of the cold end orifice diameter. Exergy efficiency decreases with increase in L/D ratio. It is also concluded that diverging vortex tube produces lower exergy loss as compared to plain tube. Valve angles have significant effect on hot end exergy loss of the vortex tube.