A CFD investigation of flow separation in an elliptical and circular Ranque-Hilsch vortex tube

Abstract

The present work investigates the flow physics inside an elliptical vortex tube. Two different 3D (three-dimensional) domains of circular and elliptical vortex tubes with four nozzles are studied. The cross-sectional area and length of the vortex tube are constant for both of its shape. The pressure at the inlet is 320 kPa for both the shapes and air as a working fluid. Standard k- ε turbulence model is used to predict the flow physics and temperature separation effect inside the tubes. The experimental and numerical findings of earlier researchers provide as validation for the present results. The deviation of the results is found within the permissible limit. The temperature separation phenomenon in an elliptical tube at various cold mass fractions is discussed. The range of cold mass fraction is 0.1 to 0.9. This work also examines the fluid characteristics and flow parameters by tracing the fluid particles within the tube. Fluid characteristics such as static pressure, density, total temperature, static temperature are evaluated. Also, the flow parameters like velocity magnitude, turbulent kinetic energy, axial velocity, and swirl velocity are discussed at the various radial locations inside the tube to get the flow pattern information. It’s an attempt to determine the feasible flow mechanism inside an elliptical vortex tube. The comparison between the circular vortex tube and the elliptical vortex tube has been done based on various fluid characteristics and temperature separation. It is found that energy separation is elevated in an elliptical tube by 49.89% at the hot end tube at 0.2 cold mass fraction whereas it is low for cold temperature separation as compared to the circular vortex.