Effect of waist drum axial position on energy separation performance of Maxwell structured tubes

Abstract

Abstract Combining numerical simulations and experimental validation, this study systematically investigates the influence of the axial position of the waist drum on the three-dimensional flow field structure and energy separation performance within Maxwell structured tubes. It is found that the waist drum position is a critical geometric parameter modulating internal momentum transfer and temperature stratification, exhibiting a significant non-monotonic relationship with energy separation efficiency. The cooling and heating effects of the system simultaneously reach their peaks when the waist drum is located in the middle region of the tube. Mechanism analysis reveals that this optimal position achieves the best synergy between flow field stability and secondary flow enhancement: it avoids the vortex core breakdown near the inlet caused by an upstream position, while overcoming the insufficient effective separation length associated with a downstream position. This research elucidates the kinetic-thermal energy conversion mechanism within variable cross-section vortex tubes, providing a theoretical basis for the topological optimization of Maxwell structured tubes.