Hydrothermal performance of hybrid nanofluid in a complex wavy porous cavity imposing a magnetic field

Abstract

Near wall surface phenomena can significantly influence the thermo-fluid flow behavior. To explore the fundamental aspects of the complex wavy walled enclosure, an attempt has been taken in this work. In this work, numerical experimentation is carried out to understand the transport phenomena of magnetohydrodynamic (MHD) buoyancy-driven thermo-fluid flow in a complex porous enclosure packed with Al2O3–Cu/water hybrid nanofluid. The main target of this study is to inspect the thermophysical phenomena by varying the amplitude (A = 0–0.3) and undulation (N = 1–8) along with other flow controlling parameters like modified Rayleigh number, (Ram = 10–104), Darcy number, (Da = 10-5–10-1), and Hartmann number, (Ha = 0–70), in their reasonable practical parametric range. The constitutive equations are solved after linearized and discretized in dimensionless form through a written computing code. The results of the investigations are presented through flow structure (streamlines), temperature distribution (isotherms), and average heat transfer rate (Nusselt number, Nu). This study reveals that the increase in the heating surface area due to the surface waviness does not always assure enhancement in heat transfer, but can be beneficial depending on the controlling parameters. An enhanced heat transfer of ∼ 20% compared to a no-waviness is achieved due to an increase in the effective length of the wavy wall. Maximum heat transfer is noted with n = 4, beyond which decreasing trend of heat transfer is noted. This analysis has possible uses of relevant thermal storage systems pertaining to enhanced heat transfer.