Numerical simulation of turbulent flow in a Ranque–Hilsch vortex tube

The present work is about numerical simulations of the internal flow in a commercial model of a Ranque–Hilsch vortex tube (RHVT) operating in jet impingement. Simulation of the turbulent, compressible, high swirling flow was performed by both RANS and LES techniques. The effect of different turbulence closure models have been tested in RANS simulations using a first order closure RNG k–ε and, for the first time in this kind of flow, a second order RSM (Reynolds Stress differential Model) closure. RANS computations have been executed on an axis-symmetric two-dimensional mesh and results have been compared with LES ones, obtained over a three-dimensional computational grid. Smagorinsky sub-grid scale model was used in LES. All the calculations were performed using FLUENT™ 6.3.26. The use of a common code for the different simulations allowed the comparison of the performances of the different techniques and turbulence models, avoiding the introduction of other variables.