Open Access

ARTICLE

Hybrid Nanofluids Mixed Convection inside a Partially Heated Square Enclosure with Driven Sidewalls

Meriem Bounib¹, Aicha Bouhezza^2,3,*, Abdelkrim Khelifa⁴, Mohamed Teggar⁵, Hasan Köten⁶, Aissa Atia⁷, Yassine Cherif ⁸

1 Laboratory LPCRI, Department of Physics, Sciences Faculty, 20 August 1955-Skikda University, Skikda, 21000, Algeria
2 Department of Technology, Faculty of Technology, 20 August 1955-Skikda University, Skikda, 21000, Algeria
3 Laboratoire LITE, Constantine 1 University, Constantine, 25000, Algeria
4 Unité de Recherche Appliquée en Energies Renouvelables URAER, Centre Développement des Energies Renouvelables CDER, Ghardaïa, 47133, Algeria
5 Laboratory of Mechanics, Amar Telidji University, BP 37G, Laghouat, 03000, Algeria
6 Faculty of Engineering and Pure Sciences, Mechanical Engineering Department, Istanbul Medeniyet University, Istanbul, 34730, Turkey
7 Department of Physics, Higher Normal School of Laghouat, Laghouat, 03000, Algeria
8 Laboratoire de Génie Civil et géo-Environnement (LGCgE), Université d’Artois, ULR 4515, Béthune, F-62400, France

* Corresponding Author: Aicha Bouhezza. Email:

(This article belongs to the Special Issue: Advances in Computational Thermo-Fluids and Nanofluids)

Frontiers in Heat and Mass Transfer 2025, 23(4), 1323-1350. https://doi.org/10.32604/fhmt.2025.065254

Received 07 March 2025; Accepted 24 June 2025; Issue published 29 August 2025

Abstract

This study investigates laminar convection in three regimes (forced convection, mixed convection, and natural convection) of a bi-nanofluid (Cu-Al₂O₃-water)/mono-nanofluid (Al₂O₃-water) inside a square enclosure of sliding vertical walls which are kept at cold temperature and moving up, down, or in opposite directions. The enclosure bottom is heated partially by a central heat source of various sizes while the horizontal walls are considered adiabatic. The thermal conductivity and dynamic viscosity are dependent on temperature and nanoparticle size. The conservation equations are implemented in the solver ANSYS R2 (2020). The numerical predictions are successfully validated by comparison with data from the literature. Numerical simulations are carried out for various volume fractions of solid mono/hybrid-nanoparticles (), Richardson numbers (0.001 ≤ Ri ≤ 10), and hot source lengths (). Isothermal lines, streamlines, and average Nusselt numbers are analyzed. The thermal performance of nanofluids is compared to that of the base heat transfer fluid (water). Outcomes illustrate the flow characteristics significantly affected by the convection regime, hot source size, sidewall motion, and concentration of solid nanoparticles. In the case of sidewalls moving downward, using hybrid nanofluid (Cu-Al₂O₃-water) shows the highest heat transfer rate in the enclosure at Ri = 1, and volume fraction of φ = 5% where a significant increment (25.14%) of Nusselt number is obtained.

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Keywords

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