Numerical analysis of the effect of helical nozzles gap on the cooling capacity of Ranque–Hilsch vortex tube

In this article, the effect of helical nozzles on both energy separation and refrigeration phenomena in the Ranque–Hilsch Vortex Tube (RHVT) was investigated by CFD techniques. The radial gap of inlet of helical nozzle from the vortex chamber (GPL) stands as a significant designing parameter. The standard k–ɛ turbulence model was introduced to the governing equations for analyzing highly rotating complex flow field. The studied helical nozzles have the same profile shape but their radial distance from the chamber distinct them from each other. Presented numerical results show that operating the vortex tube with GPL = 0.034 leads to the maximum cooling effect and swirl velocity. Furthermore, by keeping GPL value constant, the effect of number of nozzles is studied in more detail. Present results in this article, show increasing of temperature separation due to increase of nozzle numbers, however the coefficient of performance (COP) does not change very significantly.

► We investigated the effect of helical nozzle shape on the energy separation in a vortex tube. ► Results show that helical nozzles help to increase cold temperature separation. ► These types of nozzles also increase the swirl velocity magnitude in the tube. ► A number of nozzles were investigated and result shows the increase of temperature separation by increase of nozzle numbers.