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Effect of magnetic field-dependent thermal conductivity on natural convection of magnetic nanofluid inside a square enclosure

Mohammadhossein Hajiyan (School of Engineering, University of Guelph College of Physical and Engineering Science, Guelph, Canada)
Shohel Mahmud (School of Engineering, University of Guelph College of Physical and Engineering Science, Guelph, Canada)
Mohammad Biglarbegian (School of Engineering, University of Guelph College of Physical and Engineering Science, Guelph, Canada)
Hussein A. Abdullah (School of Engineering, University of Guelph College of Physical and Engineering Science, Guelph, Canada)
A. Chamkha (Department of Mechanical Engineering, Prince Mohammad Bin Fahd University, Al-Khobar, Saudi Arabia, and RAK Research and Innovation Center, American University of Ras Al Khaimah, Ras Al Khaimah, United Arab Emirates)

International Journal of Numerical Methods for Heat & Fluid Flow

ISSN: 0961-5539

Article publication date: 28 November 2018

Issue publication date: 6 June 2019

153

Abstract

Purpose

The purpose of this paper is to investigate the convective heat transfer of magnetic nanofluid (MNF) inside a square enclosure under uniform magnetic fields considering nonlinearity of magnetic field-dependent thermal conductivity.

Design/methodology/approach

The properties of the MNF (Fe3O4+kerosene) were described by polynomial functions of magnetic field-dependent thermal conductivity. The effect of the transverse magnetic field (0 < H < 105), Hartmann Number (0 < Ha < 60), Rayleigh number (10 <Ra <105) and the solid volume fraction (0 < φ < 4.7%) on the heat transfer performance inside the enclosed space was examined. Continuity, momentum and energy equations were solved using the finite element method.

Findings

The results show that the Nusselt number increases when the Rayleigh number increases. In contrast, the convective heat transfer rate decreases when the Hartmann number increases due to the strong magnetic field which suppresses the buoyancy force. Also, a significant improvement in the heat transfer rate is observed when the magnetic field is applied and φ = 4.7% (I = 11.90%, I = 16.73%, I = 10.07% and I = 12.70%).

Research limitations/implications

The present numerical study was carried out for a steady, laminar and two-dimensional flow inside the square enclosure. Also, properties of the MNF are assumed to be constant (except thermal conductivity) under magnetic field.

Practical implications

The results can be used in thermal storage and cooling of electronic devices such as lithium-ion batteries during charging and discharging processes.

Originality/value

The accuracy of results and heat transfer enhancement having magnetic field-field-dependent thermal conductivity are noticeable. The results can be used for different applications to improve the heat transfer rate and enhance the efficiency of a system.

Keywords

Citation

Hajiyan, M., Mahmud, S., Biglarbegian, M., Abdullah, H.A. and Chamkha, A. (2019), "Effect of magnetic field-dependent thermal conductivity on natural convection of magnetic nanofluid inside a square enclosure", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 29 No. 4, pp. 1466-1489. https://doi.org/10.1108/HFF-07-2018-0374

Publisher

:

Emerald Publishing Limited

Copyright © 2018, Emerald Publishing Limited

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