Infrared thermography of wall temperature distribution caused by convection of magnetic fluid

Peter Szabo, Milos Bekovic, Wolf-Gerrit Fruh

Research output: Contribution to journalArticle

Abstract

Convection of a magnetic fluid within a perspex container was investigated experimentally and complemented by a computational Finite-Element model built according to the same physical specification. The enclosure was heated at two opposite side walls and exposed to a magnetic field provided by a Neodymium-Iron-Boron permanent magnet placed either above or below the container. The spatial temperature distribution on the front side wall of the container was recorded via infrared thermography (IR) and compared to computational results that reproduced the spatial temperature fields. The results show a significant effect on heat transfer by the location of the permanent magnet and gave evidence that the Kelvin body force can be much stronger than
buoyancy. As both body forces are temperature sensitive an increase in temperature difference increased both, buoyancy and Kelvin body force, albeit with a different intensity that was explained via Curie's Law and expressed
as a temperature dependent magnetisation through the pyromagnetic coefficient, K. The heat transfer was characterised by the Nusselt number and a suitable modified Rayleigh number that took the orientation of both buoyancy and Kelvin body force in account. The degree of heat transfer enhancement reported varied between a 23% reduction to a 20% enhancement.
Original languageEnglish
Pages (from-to)129-139
Number of pages11
JournalInternational Journal of Thermal Sciences
Volume134
Early online date11 Aug 2018
DOIs
Publication statusPublished - Dec 2018

Fingerprint

Magnetic fluids
Containers
Temperature distribution
Heat transfer
Buoyancy
Permanent magnets
Neodymium
Nusselt number
Enclosures
Temperature
Boron
Magnetization
Magnetic fields
Iron
Specifications
Convection

Keywords

  • Infrared thermography
  • Natural convection
  • Magnetic convection
  • Thermomagnetic convection
  • Magnetic fluid
  • In-situ calibration

Cite this

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abstract = "Convection of a magnetic fluid within a perspex container was investigated experimentally and complemented by a computational Finite-Element model built according to the same physical specification. The enclosure was heated at two opposite side walls and exposed to a magnetic field provided by a Neodymium-Iron-Boron permanent magnet placed either above or below the container. The spatial temperature distribution on the front side wall of the container was recorded via infrared thermography (IR) and compared to computational results that reproduced the spatial temperature fields. The results show a significant effect on heat transfer by the location of the permanent magnet and gave evidence that the Kelvin body force can be much stronger thanbuoyancy. As both body forces are temperature sensitive an increase in temperature difference increased both, buoyancy and Kelvin body force, albeit with a different intensity that was explained via Curie's Law and expressedas a temperature dependent magnetisation through the pyromagnetic coefficient, K. The heat transfer was characterised by the Nusselt number and a suitable modified Rayleigh number that took the orientation of both buoyancy and Kelvin body force in account. The degree of heat transfer enhancement reported varied between a 23{\%} reduction to a 20{\%} enhancement.",
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Infrared thermography of wall temperature distribution caused by convection of magnetic fluid. / Szabo, Peter; Bekovic, Milos; Fruh, Wolf-Gerrit.

In: International Journal of Thermal Sciences, Vol. 134, 12.2018, p. 129-139.

Research output: Contribution to journalArticle

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AU - Bekovic, Milos

AU - Fruh, Wolf-Gerrit

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AB - Convection of a magnetic fluid within a perspex container was investigated experimentally and complemented by a computational Finite-Element model built according to the same physical specification. The enclosure was heated at two opposite side walls and exposed to a magnetic field provided by a Neodymium-Iron-Boron permanent magnet placed either above or below the container. The spatial temperature distribution on the front side wall of the container was recorded via infrared thermography (IR) and compared to computational results that reproduced the spatial temperature fields. The results show a significant effect on heat transfer by the location of the permanent magnet and gave evidence that the Kelvin body force can be much stronger thanbuoyancy. As both body forces are temperature sensitive an increase in temperature difference increased both, buoyancy and Kelvin body force, albeit with a different intensity that was explained via Curie's Law and expressedas a temperature dependent magnetisation through the pyromagnetic coefficient, K. The heat transfer was characterised by the Nusselt number and a suitable modified Rayleigh number that took the orientation of both buoyancy and Kelvin body force in account. The degree of heat transfer enhancement reported varied between a 23% reduction to a 20% enhancement.

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