Numerical Analysis on Flow Behavior and Energy Separation in a Vortex Tube

The vortex tube is a simple device, without any moving parts, that separates a pressurized flow of air (or any inert gas) into hot and cold streams without anychemical reactions or external energy supply. A source of pressurized gas enters the vortex tube tangentially through one or more inlet nozzle intakes with highspeed. The gas stream inside the vortex tube develops a strong swirling flow and separates into a cold and hot stream. The main objective of this paper is to study theeffect of inlet gas pressure change, inlet gas temperature change, nozzles number of a vortex tube and cold exitdiameter on energy separation phenomenon within a counter-flow vortex tube. The computational fluid dynamics (CFD) model is a three-dimensional steadycompressible model that utilizes the k-ɛ turbulence model. The results showed that increasing of the inlet pressure decreases the cold outlet temperature. It isobserved that increasing the inlet gas temperature leads to greater temperature separation, as well as greater hotand cold temperature separation. It is found that as the number of nozzles is increased, power of cooling increases significantly while cold outlet temperaturedecreases moderately. The optimum cold end diameter (dc) for obtaining the maximum hot gas temperature and minimum cold gas temperature is obtained through CFDanalysis. Validation of a previous experimental study that used a cylindrical vortex tube has also been carried out in this research.