The present study investigates magnetohydrodynamic (MHD) natural convection of Al2O3-water nanofluid in a wavy square cavity containing a heated semicircular obstacle using the Finite Element Method (FEM). The top wavy wall of the cavity is maintained at a cold temperature (Tc), while the bottom wall and semicircular obstacle are heated to a higher temperature (Th), with the vertical walls kept thermally insulated. Parametric analysis is carried out for Rayleigh numbers in the range of 103 ≤ Ra ≤ 105, nanoparticle volume fractions 0 ≤ φ ≤ 0.05, and Hartmann numbers 0 ≤ Ha ≤ 100. Flow structures and heat transport are illustrated through streamlines, isotherms, velocity, and temperature profiles, along with the average Nusselt number. Results show that increasing Ra enhances buoyancy-driven convection and improves heat transfer, while higher nanoparticle volume fractions (φ) further augment the thermal performance due to enhanced conductivity of the nanofluid. In contrast, stronger magnetic fields (higher Ha) suppress convective circulation and reduce heat transfer rates. A maximum enhancement of approximately 19.8% in Nuav is observed at φ = 0.05 compared with the base fluid, whereas heat transfer decreases noticeably with increasing Ha. The combined effects of cavity geometry, nanoparticle loading, and magnetic field highlight the complex interplay between buoyancy and Lorentz forces, offering valuable insights for the design of thermally efficient nanofluid-based systems.
References
[1]
Sheikholeslami, M. (2022) Modeling Investigation for Energy Storage System Including Mixture of Paraffin and ZnO Nano-Powders Considering Porous Media. JournalofPetroleumScienceandEngineering, 219, Article ID: 111066. https://doi.org/10.1016/j.petrol.2022.111066
[2]
Uddin, M.J., Al-Balushi, J., Mahatabuddin, S. and Rahman, M.M. (2022) Convective Heat Transport for Copper Oxide-Water Nanofluid in an Isosceles Triangular Cavity with a Rippled Base Wall in the Presence of Magnetic Field. InternationalJournalofThermofluids, 16, Article ID: 100195. https://doi.org/10.1016/j.ijft.2022.100195
[3]
Runa, A.A., Alim, M.A., Alam, M.S. and Kabir, K.H. (2022) Finite Element Analysis of Magnetohydrodynamic Natural Convection within Semi-Circular Top Enclosure with Triangular Obstacles. AmericanJournalofComputationalMathematics, 12, 33-43. https://doi.org/10.4236/ajcm.2022.121004
[4]
Bülbül, H., Atalay, T., Yakut, Y., Özbektaş, S. and Köysal, Y. (2025) Investigation of the Effect of Natural Convection Cooling Caused by the Chimney Effect on the Improved Solar Thermoelectric System. AppliedThermalEngineering, 263, Article ID: 125431. https://doi.org/10.1016/j.applthermaleng.2025.125431
[5]
Putra, N., Roetzel, W. and Das, S.K. (2002) Natural Convection of Nano-Fluids. HeatandMassTransfer, 39, 775-784. https://doi.org/10.1007/s00231-002-0382-z
[6]
Brinkman, H.C. (1952) The Viscosity of Concentrated Suspensions and Solutions. TheJournalofChemicalPhysics, 20, 571-571. https://doi.org/10.1063/1.1700493
[7]
Abu-Nada, E., Masoud, Z., Oztop, H.F. and Campo, A. (2010) Effect of Nanofluid Variable Properties on Natural Convection in Enclosures. InternationalJournalofThermalSciences, 49, 479-491. https://doi.org/10.1016/j.ijthermalsci.2009.09.002
[8]
Nasrin, R., Alim, M.A. and Chamkha, A.J. (2012) Combined Convection Flow in Triangular Wavy Chamber Filled with Water-CuO Nanofluid: Effect of Viscosity Models. InternationalCommunicationsinHeatandMassTransfer, 39, 1226-1236. https://doi.org/10.1016/j.icheatmasstransfer.2012.06.005
[9]
parvin, S., Nasrin, R. and Alim, M.A. (2014) Heat Transfer Performance of Nanofluid in a Complicated Cavity Due to Prandtl Number Variation. ProcediaEngineering, 90, 377-382. https://doi.org/10.1016/j.proeng.2014.11.865
[10]
Zahan R, I. and MA Alim, N. (2018) MHD Effect on Conjugate Heat Transfer in a Nanofluid Filled Rectangular Enclosure. InternationalJournalofPetrochemicalScience&Engineering, 3, 114-123. https://doi.org/10.15406/ipcse.2018.03.00085
[11]
Alsabery, A.I., Tayebi, T., Chamkha, A.J. and Hashim, I. (2018) Effects of Non-Homogeneous Nanofluid Model on Natural Convection in a Square Cavity in the Presence of Conducting Solid Block and Corner Heater. Energies, 11, Article 2507. https://doi.org/10.3390/en11102507
[12]
Saha, T., Islam, T., Yeasmin, S. and Parveen, N. (2023) Thermal Influence of Heated Fin on MHD Natural Convection Flow of Nanofluids Inside a Wavy Square Cavity. InternationalJournalofThermofluids, 18, Article ID: 100338. https://doi.org/10.1016/j.ijft.2023.100338
[13]
Rashid, U., Lu, D. and Iqbal, Q. (2023) Nanoparticles Impacts on Natural Convection Nanofluid Flow and Heat Transfer Inside a Square Cavity with Fixed a Circular Obstacle. CaseStudiesinThermalEngineering, 44, Article ID: 102829. https://doi.org/10.1016/j.csite.2023.102829
[14]
Ibáñez, G., Cuevas, S. and López de Haro, M. (2006) Optimization of a Magnetohydrodynamic Flow Based on the Entropy Generation Minimization Method. InternationalCommunicationsinHeatandMassTransfer, 33, 295-301. https://doi.org/10.1016/j.icheatmasstransfer.2005.12.003
[15]
Islam, T., Alam, M.N., Asjad, M.I., Parveen, N. and Chu, Y. (2021) Heatline Visualization of MHD Natural Convection Heat Transfer of Nanofluid in a Prismatic Enclosure. ScientificReports, 11, Article No. 10972. https://doi.org/10.1038/s41598-021-89814-z
[16]
Jani, S., Mahmoodi, M. and Amini, M. (2013) Magnetohydrodynamic Free Convection in a Square Cavity Heated from Below and Cooled from Other Walls. International Journal of Mechanical, Aerospace, Industrial, Mechatronic and Manufacturing Engineering, 7, 750-755.
[17]
Einstein, A. (1906) Eine neue Bestimmung der Moleküldimensionen. Annalen der Physik, 324, 289-306. https://doi.org/10.1002/andp.19063240204
[18]
Batchelor, G.K. (2016) The Effect of Brownian Motion on the Bulk Stress in a Suspension of Spherical Particles. Exercer, 83, 40-41.
[19]
Xu, G., Fu, J., Dong, B., Quan, Y. and Song, G. (2019) A Novel Method to Measure Thermal Conductivity of Nanofluids. InternationalJournalofHeatandMassTransfer, 130, 978-988. https://doi.org/10.1016/j.ijheatmasstransfer.2018.11.014
[20]
Raja, R.A.A., Sunil, J. and Maheswaran, R. (2018) Estimation of Thermo-Physical Properties of Nanofluids Using Theoretical Correlations. International Journal of Applied Engineering Research, 13, 7950-7953.
[21]
Jahan, A., Edwards, K.L. and Bahraminasab, M. (2016) Multi-Criteria Decision Analysis for Supporting the Selection of Engineering Materials in Product Design. Butter-worth-Heinemann.
[22]
Zheng, N., Liu, P., Liu, Z. and Liu, W. (2017) Numerical Simulation and Sensitivity Analysis of Heat Transfer Enhancement in a Flat Heat Exchanger Tube with Discrete Inclined Ribs. InternationalJournalofHeatandMassTransfer, 112, 509-520. https://doi.org/10.1016/j.ijheatmasstransfer.2017.05.019
[23]
Fereidooni, J. (2023) Baffles’ Size Impact on the Heat Transfer and Second Law Features of Magnetic Hybrid Nanofluid within a Hexagonal-Shaped Porous Domain. JournalofMagnetismandMagneticMaterials, 582, Article ID: 171037. https://doi.org/10.1016/j.jmmm.2023.171037
[24]
Raizah, Z. and Aly, A.M. (2021) Effect of Dual-Rotation on MHD Natural Convection of NEPCM in a Hexagonal-Shaped Cavity Based on Time-Fractional ISPH Method. ScientificReports, 11, Article No. 22687. https://doi.org/10.1038/s41598-021-02046-z
[25]
Vahedi, S.M., Zare Ghadi, A. and Valipour, M.S. (2018) Application of Response Surface Methodology in the Optimization of Magneto-Hydrodynamic Flow around and through a Porous Circular Cylinder. JournalofMechanics, 34, 695-710. https://doi.org/10.1017/jmech.2018.1
[26]
Islam, T., Gama, S. and Martins Afonso, M. (2024) Artificial Neural Network and Response Surface Methodology-Driven Optimization of Cu-Al2O3/Water Hybrid Nanofluid Flow in a Wavy Enclosure with Inclined Periodic Magnetohydrodynamic Effects. Mathematics, 13, Article 78. https://doi.org/10.3390/math13010078
[27]
Islam, S., Bairagi, T., Islam, T., Rana, B.M.J., Reza‐E‐Rabbi, S. and Rahman, M.M. (2022) Heatline Visualization in Hydromagnetic Natural Convection Flow Inside a Prismatic Heat Exchanger Using Nanofluid. InternationalJournalofThermofluids, 16, Article ID: 100248. https://doi.org/10.1016/j.ijft.2022.100248
[28]
Rahman, M.M., Öztop, H.F., Joarder, A.H., Saidur, R., Hamzah, N., Al-Salem, K. and Ibrahim, T.A. (2016) Unsteady Analysis of Natural Convection in a Carbon Nanotube-Water Filled Cavity with an Inclined Heater. Numerical Heat Transfer, Part A: Applications, 69, 794-809. https://doi.org/10.1080/10407782.2015.1090825
[29]
Garnett, J.C.M., (1904) Colours in Metal Glasses and in Metallic Film. Proceedings of the Royal Society of London, 203, 359-371.
[30]
Ghasemi, B., Aminossadati, S.M. and Raisi, A. (2011) Magnetic Field Effect on Natural Convection in a Nanofluid-Filled Square Enclosure. InternationalJournalofThermalSciences, 50, 1748-1756. https://doi.org/10.1016/j.ijthermalsci.2011.04.010
