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A mechanical device with no moving parts, a vortex tube can generate cold and hot gas flows from compressed gas. This paper investigates the effect of using a divergent hot tube on vortex tube refrigeration capacity. The computational fluid dynamics (CFD) model used is a three-dimensional steady compressible model utilizing the k-ɛ turbulence model. In this numerical research, different divergence angles of the hot tube (β=0°, 1°, 2°, 3°, 4°, and 6°) have been simulated to analyze the performance of the vortex tube. The results showed that as the angle diverges from β=0°, cold temperature separation improves at cold mass fractions greater than about 0.4, but increasing the angle to more than 4° impairs cold temperature separation compared with the cylindrical model because a secondary circulation develops in the vortex tube. Validation of a previous experimental study that used a cylindrical vortex tube has also been performed in this research.
Vortex tube, Divergent hot tube, Numerical simulation, Energy separation.
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