Enhanced conjugate natural convection in a corrugated porous enclosure with Ag-MgO hybrid nanofluid

Abstract

Understanding the impact of hybrid nanofluids (NF) on natural convection (NC) within complex enclosures can significantly advance the efficiency of heat transfer (HT) mechanisms. These advancements play a crucial role in various engineering applications, such as thermal systems in electronics, energy conversion, and heat exchangers. This study numerically examined the NC taking place within a sinusoidal corrugated enclosure filled with an Ag-MgO hybrid NF. This system was heated differentially by a vertical solid wall. The vertical right wall of the solid is maintained at an isothermal at a high-temperature Th, while the left vertical wall of the cavity is kept at an isothermal at a low-temperature Tc. The vertical left wall of the solid is in contact with the porous medium (PM) saturated with the cavity's hybrid NF. In contrast, the top and bottom horizontal walls are maintained adiabatic. The governing equations were solved by employing the Galerkin weighted residual finite elements approach. The porous domain is modeled by employing the Darcy-Brinkman formulation. The parameters being studied encompass the Darcy number (10−5 ≤ Da ≤ 10−2), Rayleigh number (103 ≤ Ra ≤ 106), nanoparticle volume fraction (0 ≤ ϕ ≤ 0.04), amplitude of waviness (0.05 ≤ A ≤ 0.2), and number of undulations (1 ≤ N ≤ 4). The results highlighted that the introduction of hybrid nanoparticles into the pure fluid enhances the HT rate across the parameter spectrum. The highest average Nusselt number (Nuav) is attained at Ra = 106, Da = 10−2, A = 0.2 and N = 4. The findings of the current study have practical implications for current industrial applications, particularly in the cooling of electronic devices.

Keywords

• Conjugate natural convection
• Corrugated enclosure
• Porous medium
• Hybrid nanofluids
• Heat transfer enhancement