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Numerical Investigation of Natural Convection and Entropy Generation in a Square Enclosure Filled with Cu-Fe₃O₄/Water Hybrid Nanofluid under the Impact of Discrete Heat Sources
Subject area: Science,Engineering and Technology · Area of research: Fluid Dynamics
DOI: 10.64388/ire1725053
Abstract
This study investigates magnetohydrodynamic (MHD) natural convection and total entropy generation of a Cu-Fe₃O₄/water hybrid nanofluid in a two-dimensional square enclosure equipped with a discrete bottom heat source. The left and right vertical walls are maintained at a cold temperature Tc, the top horizontal boundary is thermally insulated, and the bottom horizontal wall features a centrally positioned localized heat source kept at a high temperature Th. The non-dimensional governing conservation equations—mass, momentum, and thermal energy—are solved numerically using the Finite Volume Method (FVM) coupled with the SIMPLE algorithm. The investigation evaluates a parametric domain: Rayleigh number (10³ ≤ Ra ≤ 10⁶), Hartmann number (0 ≤ Ha ≤ 60), solid volume fraction of hybrid nanoparticles (0 ≤ φ ≤ 0.04), and heat source length (0.2 ≤ ε ≤ 0.8). Results show that increasing the Rayleigh number and expanding the heat source length enhance natural convection strength, local/average Nusselt numbers (Nu), and total entropy generation. Conversely, applying a magnetic field (Ha > 0) induces opposing Lorentz forces that suppress fluid circulation, dampening convective heat transfer and overall irreversibility. The addition of Cu-Fe₃O₄ hybrid nanoparticles yields superior heat transfer rates compared to single-nanoparticle suspensions and pure water. Bejan number (Be) analysis demonstrates a transition from thermal-irreversibility domination at low Ha to viscous and magnetic irreversibility domination at higher magnetic field strengths.
Keywords
Natural convection, entropy generation, Cu-Fe₃O₄ hybrid nanofluid, discrete heat source, magnetohydrodynamics (MHD), finite volume method, Bejan number
References
[1] Brinkman HC. The viscosity of concentrated suspensions and solutions. The Journal of Chemical Physics. 1952;20(4):571.
[2] Maxwell JC. A treatise on electricity and magnetism. Oxford: Clarendon Press; 1873.
[3] de Vahl Davis G. Natural convection of air in a square cavity: A bench mark numerical solution. International Journal for Numerical Methods in Fluids. 1983;3(3):249–264.
[4] Ghalambaz M, Hashem Zadeh SM, Veismoradi A, Sheremet MA, Pop I. Free convection heat transfer and entropy generation in an odd-shaped cavity filled with a Cu-Al2O3 hybrid nanofluid. Symmetry. 2021;13(1):122. https://doi.org/10.3390/sym13010122
[5] Tayebi T, Chamkha AJ. Entropy generation analysis during MHD natural convection flow of Cu-Al2O3/water hybrid nanofluid in a square cavity. Entropy. 2020;22(1):85.
[6] Kardgar A. Natural convection and entropy generation of non-Newtonian hybrid Cu-Al2O3/water nanofluid in an inclined partial porous cavity with different local heater positions in the presence of magnetic field. Journal of Heat and Mass Transfer Research. 2023;10(2):279–300. https://doi.org/10.22075/jhmtr.2023.30638.1442
[7] Selimefendigil F, Öztop HF. Effects of conductive curved partition and magnetic field on natural convection and entropy generation in an inclined cavity filled with nanofluid. Physica A: Statistical Mechanics and its Applications. 2020;540:123004.
[8] Aminossadati SM, Ghasemi B. Natural convection cooling of a localised heat source at the bottom of a nanofluid-filled enclosure. European Journal of Mechanics - B/Fluids. 2009;28(5):630–640.
How to cite this paper
@article{1725053,
author = {S. Gowtham},
title = {Numerical Investigation of Natural Convection and Entropy Generation in a Square Enclosure Filled with Cu-Fe₃O₄/Water Hybrid Nanofluid under the Impact of Discrete Heat Sources},
journal = {Iconic Research And Engineering Journals},
year = {2026},
volume = {10},
number = {5},
pages = {2451-2458},
issn = {2456-8880},
url = {https://www.irejournals.com/formatedpaper/1725053.pdf},
abstract = {This study investigates magnetohydrodynamic (MHD) natural convection and total entropy generation of a Cu-Fe₃O₄/water hybrid nanofluid in a two-dimensional square enclosure equipped with a discrete bottom heat source. The left and right vertical walls are maintained at a cold temperature Tc, the top horizontal boundary is thermally insulated, and the bottom horizontal wall features a centrally positioned localized heat source kept at a high temperature Th. The non-dimensional governing conservation equations—mass, momentum, and thermal energy—are solved numerically using the Finite Volume Method (FVM) coupled with the SIMPLE algorithm. The investigation evaluates a parametric domain: Rayleigh number (10³ ≤ Ra ≤ 10⁶), Hartmann number (0 ≤ Ha ≤ 60), solid volume fraction of hybrid nanoparticles (0 ≤ φ ≤ 0.04), and heat source length (0.2 ≤ ε ≤ 0.8). Results show that increasing the Rayleigh number and expanding the heat source length enhance natural convection strength, local/average Nusselt numbers (Nu), and total entropy generation. Conversely, applying a magnetic field (Ha > 0) induces opposing Lorentz forces that suppress fluid circulation, dampening convective heat transfer and overall irreversibility. The addition of Cu-Fe₃O₄ hybrid nanoparticles yields superior heat transfer rates compared to single-nanoparticle suspensions and pure water. Bejan number (Be) analysis demonstrates a transition from thermal-irreversibility domination at low Ha to viscous and magnetic irreversibility domination at higher magnetic field strengths.},
keywords = {Natural convection, entropy generation, Cu-Fe₃O₄ hybrid nanofluid, discrete heat source, magnetohydrodynamics (MHD), finite volume method, Bejan number},
month = {November},
doi = {https://doi.org/10.64388/ire1725053}
}