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A study of natural convection heat transfer in a nanofluid filled enclosure with elliptic inner cylinder

M. Sheikholeslami (Department of Mechanical Engineering, University of Mazandaran, Babolsar, Iran; Department of Mechanical Engineering, Islamic Azad University, Mazandaran, Iran, and Department of Mechanical Engineering, Babol University of Technology, Babol, Iran)
R. Ellahi (Department of Mathematics & Statistics, IIUI, Islamabad, Pakistan and Department of Mechanical Engineering, University of California Riverside, Riverside, California, USA)
Mohsan Hassan (Department of Mathematics & Statistics, IIUI, Islamabad, Pakistan)
Soheil Soleimani (Department of Mechanical & Materials Engineering, Florida International University, Miami, Florida, USA)

International Journal of Numerical Methods for Heat & Fluid Flow

ISSN: 0961-5539

Article publication date: 28 October 2014

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Abstract

Purpose

The purpose of this paper is to study the effects of natural convection heat transfer in a cold outer circular enclosure containing a hot inner elliptic circular cylinder. The fluid in the enclosure is Cu-water nanofluid. The main emphasis is to find the numerical treatment for the said mathematical model. The effects of Rayleigh number, inclined angle of elliptic inner cylinder, effective of thermal conductivity and viscosity of nanofluid, volume fraction of nanoparticles on the flow and heat transfer characteristics have been examined.

Design/methodology/approach

A very effective and higher order numerical scheme Control Volume-based Finite Element Method (CVFEM) is used to solve the resulting coupled equations. The numerical investigation is carried out for different governing parameters namely; the Rayleigh number, nanoparticle volume fraction and inclined angle of elliptic inner cylinder. The effective thermal conductivity and viscosity of nanofluid are calculated using the Maxwell-Garnetts (MG) and Brinkman models, respectively.

Findings

The results reveal that Nusselt number increases with an increase of nanoparticle volume fraction, Rayleigh numbers and inclination angle. Also it can be found that increasing Rayleigh number leads to a decrease in heat transfer enhancement. For high Rayleigh number the minimum heat transfer enhancement ratio occurs at.

Originality/value

To the best of the authors’ knowledge, no such analysis is available in the literature which can describe the natural convection heat transfer in a nanofluid filled enclosure with elliptic inner cylinder by means of CVFEM.

Keywords

Acknowledgements

Mohsan Hassan is grateful to the Higher Education Commission Pakistan to award him Indigenous Scholarship for his PhD studies.

Citation

Sheikholeslami, M., Ellahi, R., Hassan, M. and Soleimani, S. (2014), "A study of natural convection heat transfer in a nanofluid filled enclosure with elliptic inner cylinder", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 24 No. 8, pp. 1906-1927. https://doi.org/10.1108/HFF-07-2013-0225

Publisher

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Emerald Group Publishing Limited

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