Numerical Investigation of Flow Direction and Inlet–Outlet Configuration Effects on Thermo-Hydraulic Performance in T-Junction Tubes

Gürcan A.

Dicle Üniversitesi Mühendislik Fakültesi Mühendislik Dergisi, cilt.17, sa.3, ss.1-17, 2026 (TRDizin)

Özet

Direct comparisons of diverging and converging T-junction configurations under identical operating and boundary conditions remain limited, restricting the design-oriented selection of suitable flow arrangements. This study numerically investigates the effects of flow direction and inlet–outlet topology on the thermo-hydraulic performance of a symmetric equal-diameter T-junction with water as the working fluid. Four configurations were examined: axially fed and branch-fed diverging flows (K1 and K2) and opposing-stream and orthogonal-stream merging flows (K3 and K4). Three-dimensional steady Reynoldsaveraged Navier–Stokes simulations were performed in ANSYS Fluent using the standard 𝒌–𝜺 turbulence model with Enhanced Wall Treatment at Reynolds numbers of 5000, 10000, and 15000 and inlet temperatures of 313, 333, and 353 K. The configurations were compared under identical geometry, total mass flow rate, and wall-temperature conditions using the average Nusselt number, static pressure drop, and a common thermo-hydraulic performance criterion (PEC). K1 consistently provided the highest average Nusselt number and the lowest pressure drop, while K2 was the closest alternative. Relative to K1, the PEC values of K3 and K4 were lower by 43.3–53.4% and 45.0–53.5%, respectively. The results show that stronger local flow interaction in converging configurations does not necessarily yield superior overall performance and provide a quantitative basis for selecting equal-diameter T-junction topologies in water-based thermal and process-piping applications.