Performance analysis of nanofluid natural convection in an H-shaped cavity with a W-shaped baffle at various positions

Purpose The aim of this study is to numerically investigate natural convection heat transfer in an H-shaped cavity filled with Al2O3–water nanofluid, with a particular focus on the influence of W-shaped baffle geometry, its position, and relative height on the thermal performance. Design/methodology/approach A two-dimensional, steady-state numerical model was developed by solving the Navier–Stokes, continuity and energy equations using the finite volume method coupled with the SIMPLE algorithm. The effects of key governing parameters, including the Rayleigh number (104–106), nanoparticle volume fraction (0–2%), baffle position (upper, lower and combined) and relative baffle height (H/16 and H/8), were systematically analyzed. Findings The results demonstrate that both the Rayleigh number and nanoparticle volume fraction significantly enhance heat transfer. The baffle configuration plays a crucial role, with the upper baffle position yielding the highest Nusselt number, followed by the combined and lower configurations. In addition, a relative baffle height of H/8 provides slightly better thermal performance than H/16, although both configurations effectively improve convective heat transfer. Originality/value This study provides new insights into the combined effects of complex cavity geometry and nanofluid properties on natural convection. The introduction of a W-shaped baffle within an H-shaped enclosure offers an original configuration that contributes to the optimization of thermal systems and advanced heat transfer applications.