Open Access

ARTICLE

Numerical Study of the Effect of Non-Uniform Porosity on Hybrid Nanofluid Flow inside Porous Microchannel Affected by Magnetic Field

Khaleel Al Khasawneh, Mohammad Ghafar^*
Department of Mechanical Engineering, Jordan University of Science and Technology, Irbid, Jordan
* Corresponding Author: Mohammad Ghafar. Email:
(This article belongs to the Special Issue: Advances in Micro/Nano Thermal Systems for Industrial Applications: Performance Evaluation, Optimization, and Sustainable Solutions)

Frontiers in Heat and Mass Transfer https://doi.org/10.32604/fhmt.2026.084380

Received 21 April 2026; Accepted 24 August 2026; Published online 31 August 2026

Abstract

This study numerically investigated the flow of incompressible water-based hybrid nanofluid (Al₂O₃–Cu/water) in a two-dimensional horizontal microchannel with non-uniform porosity in the transverse direction. The medial region of the microchannel received a steady and uniform heat flux and was simultaneously exposed to a constant transverse magnetic field. While the remaining sections had an insulated wall without a magnetic effect. The results showed that the non-uniform porous layer suppressed the axial velocity, while the magnetic field further damped momentum by approximately 6–12% as Hartmann number increased from 0 to 40. Thermal response strongly correlated with flow inertia: the maximum dimensionless temperature increased from 0.03 at Reynolds number = 500 to 0.14 at Reynolds number = 10, confirming the dominance of conduction at low Reynolds number and convection at high Reynolds number. Increasing the hybrid nanoparticle concentration enhanced heat transfer; the local Nusselt number at the heated upper wall increased from Nu_s ≈ 36 for the base fluid to Nu_s ≈ 42–44 when using the Cu–Al₂O₃ hybrid mixture with ${\phi }_1{=\phi }_2$ = 0.04, representing a 15–20% improvement. Comparative analysis revealed that copper nanoparticles provide strong conductivity enhancement, whereas aluminum oxide improves thermal stability; they generate a synergistic effect absent in single-nanoparticle suspensions. The contour fields demonstrated a clear transition from diffusion-dominated transport (Re = 10) to convection-dominated flow (Re = 500), with isotherms tilting downstream and velocity lines becoming fully parallel at high flow rates. The numerical results show very good agreement with available analytical and numerical data for both velocity and temperature distributions. The small deviations observed confirm the accuracy and reliability of the present numerical model. Overall, the results demonstrate that combining non-uniform porosity with hybrid nanofluids under a magnetic field provides an effective approach for controlling the flow behavior and improving heat transfer performance in microchannel cooling systems. In addition, the close agreement between the present results and previously published studies confirms the accuracy and reliability of the numerical model.

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Keywords

Hybrid nanofluid; non-uniform porosity; magnetic field

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