Numerical Investigation of Turbulent Drag Reduction Mechanisms in Newtonian Fluid Pipes with Energy Promoter Rings

This study numerically investigates steady-state turbulent flow in circular pipes equipped with energy-promoter rings to enhance flow efficiency and reduce drag. Using the Reynolds-Averaged Navier–Stokes (RANS) equations with the standard k–ε turbulence model implemented in ANSYS Fluent, the effects of energy-promoter geometry and spacing were analysed for water flow at high Reynolds numbers. Mesh independence and validation against empirical correlations confirmed the reliability of the numerical model. Results show that the curved energy-promoter design consistently outperforms the simple configuration by providing smoother turbulence modulation and lower wall shear stress. Decreasing the spacing between rings enhances the drag-reduction effect, with the optimum configuration (curved design, 50 mm spacing) achieving a maximum drag-reduction efficiency of approximately 9 %. The analysis of velocity fields and pressure-drop behavior reveals that the promoters weaken near-wall turbulence and reduce energy dissipation without introducing excessive pressure penalties. These findings demonstrate the potential of passive energy-promoter rings as a cost-effective method for improving the hydraulic performance of turbulent Newtonian pipe flows in industrial transport systems.