CFD study on the effects of viscous shear in a hot cascade Ranque–Hilsch vortex tube

The objective of this paper is to carry out an extensive Computational Fluid Dynamics (CFD) study on work transfer due to viscous shear in a hot cascade Ranque–Hilsch vortex tube. The commercial CFD code ANSYS FLUENT 14.0 has been employed to carry out the numerical analysis using RANS standard k-epsilon turbulence model. A two-dimensional axisymmetric geometrical domain has been generated with structured mesh and air has been taken as the working fluid. The CFD results reveal that work transfer due to the action of viscous shear along the tangential direction increases considerably with hot cascading. However, the work transfer due to viscous shear along the axial direction degrades the performance of the device as the heat transfer takes place from cold zone to the hot zone. The effect of radial shear stress is negligible due to low value of radial velocity gradient. (paper)