Thermo-magnetohydrodynamic natural convection in corrugated enclosures with a clear nanofluid layer and a porous layer saturated by Al₂O₃/Ethylene glycol nanofluid

Document Type : Research Paper

Authors

Mechanical Engineering Department, University of Babylon, Hillah, Babylon 51001, Iraq.

Abstract

Natural convection heat transfer in corrugated enclosures has attracted increasing attention due to its importance in thermal management applications. However, the combined effects of wall corrugation, porous media, ethylene glycol–based nanofluids, and magnetic field control have not been sufficiently addressed. In the present study, a numerical investigation is carried out to analyze thermo-magnetohydrodynamic natural convection inside a corrugated enclosure subjected to different heating configurations. The enclosure is divided into two regions: an upper region filled with an ethylene glycol–based nanofluid and a lower porous layer saturated with the same nanofluid. Three heating cases are considered, namely an externally heated corrugated cylinder, an upper heated wall, and an externally heated circular boundary. The governing equations are solved using the finite element method under steady-state conditions. The effects of Rayleigh number (10⁴  up to 10⁶), Hartmann number (0 up to 60), Darcy number (10^-5  up to  10^-3), and magnetic field inclination angle (0° up to 35^o ) are examined at a fixed nanoparticle volume fraction of 0.02. The results show that increasing the Rayleigh number enhances heat transfer, while the magnetic field intensity suppresses convection. Among all cases, the externally heated corrugated cylinder provides the highest thermal performance, and the ethylene glycol–based nanofluid enhances the average Nusselt number by up to 48% at Ra = 10 ⁶.

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