<p>Improving heat transfer in pipes has gained significant attention in recent years due to its critical role in enhancing energy efficiency. Among various passive techniques, twisted tape inserts are widely recognized for their ability to enhance thermal performance by altering the flow structure and promoting turbulence. These inserts act as turbulators, generating vortex flows and disrupting the thermal boundary layer, thereby increasing the heat transfer coefficient. This study investigates the combined use of twisted tape geometries and nanoparticle-enhanced fluids on convective heat transfer performance in circular tubes. Different twist ratios of twisted tape inserts and various concentrations of hybrid nanofluids (Al₂O₃-TiO₂) were evaluated. The simulations were conducted using computational fluid dynamics (CFD) to analyze the thermal and hydrodynamic behavior of the nanofluid under different configurations. Results indicate that increasing the nanoparticle concentration significantly enhances the heat transfer rate. Among the tested configurations, the twisted tape with a twist ratio of 4 yielded the highest heat transfer improvement. The use of Al₂O₃-TiO₂ (5–3 %) hybrid nanofluid demonstrated a considerable positive impact on system performance. Performance was assessed in terms of Nusselt number, friction factor, and performance evaluation criteria (PEC), highlighting the effectiveness of the combined enhancement method.</p>