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Heat transfer and entropy generation in viscous-joule heating MHD microchannels flow under asymmetric heating

Antar Tahiri, Haroun Ragueb, Mustafa Moussaoui, Kacem Mansouri, Djemaa Guerraiche, Khelifa Guerraiche

International Journal of Numerical Methods for Heat & Fluid Flow

ISSN: 0961-5539

Article publication date: 22 August 2024

Issue publication date: 25 September 2024

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Abstract

Purpose

This paper aims to present a numerical investigation into heat transfer and entropy generation resulting from magnetohydrodynamic laminar flow through a microchannel under asymmetric boundary conditions. Furthermore, the authors consider the effects of viscous dissipation and Joule heating.

Design/methodology/approach

The finite difference method is used to obtain the numerical solution. Simulations are conducted across a broad range of Hartmann (Ha = 0 ∼ 40) and Brinkman (Br = 0.01 ∼ 1) numbers, along with various asymmetric isothermal boundaries characterized by a heating ratio denoted as ϕ.

Findings

The findings indicate a significant increase in the Nusselt number with increasing Hartmann number, regardless of whether Br equals zero or not. In addition, it is demonstrated that temperature differences between the microchannel walls can lead to substantial distortions in fluid temperature distribution and heat transfer. The results reveal that the maximum entropy generation occurs at the highest values of Ha and η (a dimensionless parameter emerging from the formulation) obtained for ϕ = −1. Moreover, it is observed that local entropy generation rates are highest near the channel wall at the entrance region.

Originality/value

The study provides valuable insights into the complex interactions between magnetic fields, viscous dissipation and Joule heating in microchannel flows, particularly under asymmetric heating conditions. This contributes to a better understanding of heat transfer and entropy generation in advanced microfluidic systems, which is essential for optimizing their design and performance.

Keywords

Acknowledgements

Declaration of competing interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Citation

Tahiri, A., Ragueb, H., Moussaoui, M., Mansouri, K., Guerraiche, D. and Guerraiche, K. (2024), "Heat transfer and entropy generation in viscous-joule heating MHD microchannels flow under asymmetric heating", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 34 No. 10, pp. 3953-3978. https://doi.org/10.1108/HFF-05-2024-0380

Publisher

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Emerald Publishing Limited

Copyright © 2024, Emerald Publishing Limited

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