Numerical Simulation of Natural Convection in Hybrid Nanofluids for Thermal Management Applications

Abstract

Hybrid nanofluids have emerged as advanced heat transfer media due to their superior thermal conductivity and stability compared to conventional single nanofluids. In this study, a numerical model was developed to investigate natural convection in an eccentric annular enclosure filled with hybrid nanofluids comprising Al₂O₃–Cu/water. The governing equations of momentum and energy were solved using the finite volume method under laminar, steady-state conditions. Results revealed that heat transfer enhancement strongly depended on nanoparticle volume fraction and eccentricity ratio of the annular space. For 4% nanoparticle concentration, the average Nusselt number increased by nearly 28% compared to base fluid, with Cu nanoparticles contributing more significantly to thermal conductivity enhancement than Al₂O₃. The flow field analysis demonstrated intensified convection currents near the inner hot wall, while higher eccentricity ratios improved heat dissipation through asymmetrical flow circulation. Entropy generation analysis further confirmed that hybrid nanofluids reduced overall irreversibilities, enhancing system efficiency. These findings underline the potential of hybrid nanofluids for thermal management in electronic cooling systems, solar collectors, and energy storage devices.