Entropy generation analysis of turbulent flow in conical tubes with dimples: a numerical study

Abstract Minimizing the entropy generation rate is one of key performance indicators for enhancing thermal design heat exchangers. This paper introduces a comprehensive numerical analysis turbulent water flow inside—newly proposed—conical tubes with dimples subjected to constant flux. The effect different tube diameter ratios (DR = 1, 1.5, 2, 3, and 5) modes (convergent divergent configurations) on thermal, viscous, total rates investigated within Reynolds number (Re) range 3 × 10 –40 using ANSYS-Fluent package. Realizable k - ε (RKE) turbulence model adopted in this study. A well-validated 3D was estimate dimensionless indices: Bejan (Be), enhanced ratio ( N s,en ), irreversibility distribution $${\phi }_{\mathrm{s}}$$ ϕ s ) characterize compare conical dimpled smooth ones. results showed that production values geometries are lower than those corresponding ones, especially convergent tubes. Convergent DR 1.5–3 achieved lowest over whole Re range, an average value 0.20 W K −1 , as compared 0.34 configurations. 0.46 0.80 at 3000 40,000, reductions 50.54% 3.61% both values, respectively. study also could provide effective tool highlight optimal exchangers based minimum ratio.