Numerical Analysis of the Flow Phenomena Inside the Vortex Tube with Different Turbulence Models

To accelerate progress toward sustainability, a fundamental shift from conventional to renewable energy sources is necessary, but insufficient on its own. Improving the efficiency of existing energy systems is equally important. One promising avenue for achieving this goal involves integrating previously overlooked devices, such as the vortex tube, into the current systems. Thus, there is a growing emphasis on overcoming its limitations, including limited development and suboptimal efficiency, to unlock its potential in diverse applications. The current focus is primarily on computational research rather than on experimental approaches due to the advantages in terms of cost and time. Nevertheless, computational studies present their own set of challenges, with two prominent hurdles being the attainment of acceptable mesh and the selection of an appropriate turbulence model. This study aims to address these challenges. An acceptable mesh has been obtained by optimization, which involves refinement of mesh at the inlet and outlet regions, followed by a comprehensive assessment of mesh independence at each stage. Furthermore, achieving a y + value of 1 in the most important regions of the vortex tube is crucial, particularly when employing low Re turbulence models, to accurately predict boundary layer behavior. Building on the mesh studies, the performance of different turbulence models is evaluated with reference data. Among the considered models, the standard k-ε turbulence model has the best performance, aligning closely with experimental results for almost the same geometric setup. As a result, the standard k-ε turbulence model is selected for further numerical investigations.