Simulation of Partial Magnetic Field effects on Cu-TiO2-water Hybrid Nanofluid Natural Convection Flow in a Darcy-Brinkman-Forchheimer Porous Media Enclosure with a MAC-FVM combined scheme

Lakshmi, C Venkata; Swetha Sri, Kakarla; Venkatadri, K; Anwar Bég, O

Abstract

This study introduces an innovative numerical analysis of natural convection heat transfer within a differentially heated square enclosure containing a porous medium, permeated by an electrically conductive hybrid nanofluid (Cu+TiO₂/water), under the effect of a localized magnetic field. Unlike conventional studies that apply uniform magnetic fields, this work introduces a partial magnetic field, allowing localized control of heat transfer and flow dynamics. The analysis is conducted using the Brinkman-Forchheimer-extended Darcy model, which accounts for both viscous and inertial effects in the porous medium, while the partial differential equations are solved using the finite volume method combined with a Marker-and-Cell (MAC) scheme for enhanced accuracy. The effects of key dimensionless parameters-thermal buoyancy parameter i.e. Rayleigh number (Ra), porosity (), Hartmann magnetic number (Ha), permeability parameter i.e. Darcy number (Da), and heat source/sink parameter (Q)-on the natural convection of thermal transport of hybrid nanofluids (Cu + Ti O₂/water) in a porous enclosure. Validation with previous computational studies is included for some special cases of the present model. An increase in Ra from 10 3 í µí±¡í µí± 10 6 enhances buoyancy-driven convection, resulting in a significant rise in the average Nusselt number (í µí±í µí±¢ í µí±) by approximately 10 times, indicating more efficient heat transfer. The partial magnetic field introduces a unique damping effect, where higher Ha values reduce convective flow and decrease heat transfer efficiency by up to 50%, highlighting its potential as a precise thermal control mechanism. With increasing porosity, the singular vortex cell morphs from a circular structure to an elliptic structure and eventually a peanut-shaped topology stretched laterally across the enclosure. These findings underscore the importance of parameter optimization for improving heat transfer efficiency in hybrid nanofluid systems, with potential applications in

• Journal Article Type: Article
• Acceptance Date: May 12, 2025
• Deposit Date: May 12, 2025
• Print ISSN: 2047-6841
• Electronic ISSN: 2047-685X
• Publisher: World Scientific Publishing
• Peer Reviewed: Peer Reviewed