Effect of Different Geometric and Physical Parameters of a Corrugated Partition Contained in a Hexagonal Enclosure Using Cu-water Nanofluid

This study presents a comprehensive numerical analysis of combined natural convection and conduction heat transfer in a sinusoidally corrugated, horizontally partitioned hexagonal enclosure filled with Cu-water nanofluid. The regular hexagonal cavity is differentially heated, with a thermally conductive solid partition dividing the domain into two regions, thereby enabling conjugate heat transfer through both the fluid and solid layers. The dimensionless governing equations for continuity, momentum, and energy are solved using the finite element method across conduction- and convection-dominated regimes. The investigation considers Cu–water nanofluid and examines the effects of varying partition thicknesses (Tp = 0.10, 0.15, 0.20) with a highly conductive material, along with key corrugation parameters, namely amplitude (0.01 ≤ A ≤ 0.10) and frequency (5 ≤ f ≤ 9). The effects of these parameters on temperature fields, streamline structures, heat transfer rate, entropy generation, and ecological coefficient of performance are systematically explored. The results reveal that higher corrugation amplitude and frequency, coupled with lower partition thickness, markedly improve the average Nusselt number, although they also elevate total entropy generation.