Numerical and experimental investigation of a phase-change material embedded in a confined space and subjected to a magnetic field

Alissar Yehya2^{2}, Philip Adebayo3^{3}, Hassane Naji1,⋆^{1,\star}
⋆^{\star} : hassane.naji@univ-artois.fr
1^{1} Univ. Artois, IMT Nord Europe, Junia, Univ. Lille, ULR 4515, Laboratoire de Génie Civil et géo-Environnement (LGCgE), F-62400 Béthune
2^{2} Maroun Semaan Faculty of Engineering and Architecture, American University of Beirut, Civil and Environmental Engineering Dept.
3^{3} Maroun Semaan Faculty of Engineering and Architecture, American University of Beirut, Mechanical Engineering Dept.
Mots clés : Phase change materials (PCM), magnetic field, latent heat, fusion, heat flux, Lorentz force, binding energy
Résumé :

In phase-change materials (PCMs) applications, melting occurs at nearly constant temperature,thus avoiding ambient temperature fluctuations. Thereby, the melting time control can be useful to maintain thermal comfort at lower energy demand. This experimental and numerical study deals with the impact of using a uniform magnetic field on the melting rate of an organic PCM placed in an aluminum enclosure. The effect of magnetic field is modeled by including the Lorentz force as a source term in the momentum equations, which are fully coupled with the energy equations [1, 2]. From the numerical simulations, it turned out that a substantial reduction in the liquid fraction can be obtained for high Hartmann numbers, controlled by the magnetic field intensity and the enclosure aspect ratio, and when the direction of the applied Lorentz force is opposite to the buoyant force. On the other hand, experimentally, the PCM was placed inside an aluminum enclosure and permanent magnets of different dimensions and strengths were added to the bottom of it. The enclosure was subjected to a thermal load through heat exchanger plates controlled by a thermoregulating bath [3]. Analyzing the experimental data, retrieved from embedded heat flux sensors and thermocouples, demonstrates that the effect of increasing the magnetic field on heat flux is in accordance with the numerical results. A reduction in the time for fusion is obtained when the magnetic field is applied vertically opposing buoyancy.

Keywords: Phase change materials (PCM), magnetic field, latent heat, fusion, heat flux, Lorentz force.

References

[1] Doostani A., Ghalambaz M., Chamkha A.J. MHD natural convection phase-change heat transfer in a cavity: analysis of the magnetic field effect. J. Braz. Soc. Mech. Sci. Eng. 39, 2831-2846, 2017. https://doi.org/10.1007/s40430-017-0722-z

[2] Adebayo P., Yehya A. The effect of combining magnetic field and high-conductivity nanoparticles on the fusion rate of a phase change material. Energy Convers. Manag. 16, 100314, 2022. https://doi.org/10.1016/j.ecmx.2022.100314

[3] Yehya A., Naji H., Zalewski L. Experimental and numerical characterization of an impure phase change material using a thermal lattice Boltzmann method. Appl. Therm. Eng. 154, 738-750, 2019. https://doi.org/10.1016/j.applthermaleng.2019.03.026

doi : https://doi.org/10.25855/SFT2023-116

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