Finned circular‑tube heat exchangers are critical components in power, transportation, and HVAC systems; however, their thermal‑hydraulic performance is limited by wake‑induced separation and recirculation, which elevate pressure losses and compromise downstream heat transfer. This study introduces a novel enhanced fin pattern that integrates upstream louvered fins with rear‑punched curved delta‑winglet vortex generators (CWVGs), synergistically combining periodic boundary‑layer renewal with intensified secondary flows. A validated 3D CFD framework (RNG k–ε) benchmarks plain, louvered, curved‑VG, and hybrid fins over Re = 1800–6450, followed by sequential optimization via Taguchi orthogonal design and response surface methodology (RSM). At fixed Re, the combined fin delivers the highest area‑averaged Nusselt number, outperforming plain fin by 61.51%–91.73%, fin with curved VG by 31.36%–48.53%, and louvered fin by 3.45%–13.33%. Although it incurs the largest friction factor, its overall enhancement factor J_F remains superior (1.34–1.50 versus plain fin), with stronger net gains at lower Re. Mechanistic analysis shows that louvers intensify upstream convection, while CWVGs compress the wake and generate robust secondary flows, yielding synergistic enhancement. Taguchi analysis identifies dominant geometric drivers and their Reynolds‑number dependence, revealing a stable, high‑performance fin‑pitch band (F_p ≈ 2.15–2.30 mm). RSM further refines key parameters, producing Re‑specific optima with high predictive fidelity, e.g., D_VG/D_c = 1.342, F_p = 1.854 mm, θ = 19.5° at Re = 1800, and D_VG/D_c = 1.320, F_p = 2.300 mm, θ = 18.0° at Re = 4100. Overall, the hybrid design and sequential Taguchi–RSM workflow provide a rigorous, data‑driven framework for engineering next‑generation, energy‑efficient finned‑tube heat exchangers with quantified performance–pressure‑drop trade‑offs.

Louvered fins,Vortex generators,Heat transfer characteristics,Taguchi method,response surface methodology (RSM)