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Thermal Conductivity of Fe2O3 and Fe3O4 Magnetic Nanofluids Under the Influence of Magnetic Field

Karimi, A ; Sharif University of Technology | 2015

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  1. Type of Document: Article
  2. DOI: 10.1007/s10765-015-1977-1
  3. Publisher: Springer New York LLC , 2015
  4. Abstract:
  5. In this paper, the thermal conductivity of water-based hematite Fe2O3 and magnetite Fe3O4 nanofluids have been investigated in the absence and presence of a uniform magnetic field. The experiments have been performed in the volume concentration range of 0 % to 4.8 % and the temperature range of 20∘C to 60∘C. The effects of the particle volume fraction, temperature, and magnetic field strength on the thermal conductivity have been analyzed. Results show that the thermal conductivity of iron oxide nanofluids has a direct relation with the particle volume fraction and temperature, without the presence of a magnetic field. But surprisingly, when the magnetic field is applied, it is observed that the thermal conductivity decreases with increasing temperature and it is also higher for a magnetite nanofluid than for a hematite nanofluid. Moreover, changes in the strength of the magnetic field cause the thermal-conductivity ratio of the ferrofluid with respect to pure water to increase from 15 % to 38.5 % and from 13 % to 175 % for magnetite and hematite nanofluids, respectively. Based on the obtained experimental results, a correlation has been developed for the thermal conductivity of iron oxide magnetic nanofluids as a function of the volume fraction, temperature, and magnetic field strength
  6. Keywords:
  7. Ferrofluid ; Magnetite ; Nanofluid ; Hematite ; Iron oxides ; Magnetic field effects ; Magnetic fluids ; Nanofluidics ; Thermal conductivity of liquids ; Volume fraction ; Increasing temperatures ; Influence of magnetic field ; Magnetic field strengths ; Nanofluids ; Particle volume fractions ; Thermal conductivity ratio ; Uniform magnetic fields ; Volume concentration ; Thermal conductivity
  8. Source: International Journal of Thermophysics ; Volume 36, Issue 10-11 , September , 2015 , Pages 2720-2739 ; 0195928X (ISSN)
  9. URL: http://link.springer.com/article/10.1007/s10765-015-1977-1#/close