PL
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Volume 128 (2015)

CONTENTS

No. 128, 2015, 29–42

The heat transfer and flow structure analyses of low concentration copper nanofluids in a strong magnetic field
ALEKSANDRA ROSZKO, ELŻBIETA FORNALIK-WAJS

Abstract

Main aim of this paper was to analyze the influence of strong magnetic field on the enhancement or suppression of nanofluids transport processes. The second objective was to determine how the flow structure changed under the influence of a magnetic field. Analyzed diamagnetic nanofluids composed of distilled water and the copper nanoparticles of 40–60 nm size in three different concentrations (50, 500, and 1000 ppm). The experimental enclosure position in the magnet test section caused the most intricate interaction of the acting forces: the gravitational and magnetic buoyancy ones, and made the interpretation of results very difficult. The Nusselt number ratio and the thermomagnetic Rayleigh number were determined for heat transfer analysis, while the fast Fourier transform was performed for the nanofluid flow structure analysis. Spectral analysis for all examined nanofluids was presented. Influence of nanoparticles concentration was clearly visible, while the direct impact of magnetic field on the heat transfer and flow structure should be still investigated.

Keywords:

nanofluids, heat transfer, flow structure, fast Fourier transform, Nusselt number ratio, thermomagnetic Rayleigh number
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