Experimental analysis of a Ranque–Hilsch vortex tube for optimizing nozzle numbers and diameter

• Interchangeable parts RHVT to investigate effects of parameters on performance.
• Effect of cold end orifice–nozzle intakes distance, no of nozzles & D on performance.
• Cold–hot Tout, isentropic efficiency & COP are presented.
• Best Poper and cold fraction, on RHVT performance are investigated.
• 2D CFD presented to extrapolate experimental data.

A brass vortex tube with changeable parts is used to obtain the optimum nozzle intake numbers and diameter. The effects of inlet pressure and CF (cold fraction) are also investigated. Results illustrate that increasing the number of nozzles causes a temperature drop and the optimum nozzle diameter corresponds to quarter of vortex tube diameter. The distance between cold end orifice and nozzle intakes is investigated in this work and it is found that for a better performance, this distance should be decreased. A series of experiments conducted to investigate the CF effect on VT performance and an optimum amount for this parameter is found. A two-dimensional computational fluid dynamics simulation of a VT has been carried out as well. CFD code is applied to investigate the role of nozzle diameter on the temperature separation. The highly rotating flow field structure and its characteristic are simulated and analyzed with respect to various operating inlet pressure ranges and different CFs. Finally, some results of the CFD models are validated by the available experimental data, showing reasonable agreement for future development.