The thermal conductivity of water base ferrofluids under magnetic field

Gavili, Anwar; Zabihi, Fatemeh; Isfahani, Taghi Dallali; Sabbaghzadeh, J.

doi:10.1016/j.expthermflusci.2012.03.016

Cited by 180 publications

(67 citation statements)

References 22 publications

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“…It is shown that the magnetic field effect on thermal conductivity of magnetic nanofluid increases with temperature rise of nanofluid. It should be noted that in [2,6] it was shown that with increasing temperature, the coefficient of thermal conductivity decreases.…”

Section: Sts-33mentioning

confidence: 99%

“…For example, in [1] was a 23 % increase in the thermal conductivity of nanofluid based on kerosene and Fe 3 O 4 nanoparticles (10 nm in size and a 7.8 % volume concentration), and 300 % in the absence of a magnetic field. The authors of [2] investigated water-based nanofluids with Fe 3 O 4 nanoparticles (10 nm in size and 5 % volume concentration) under the magnetic field action and observed a more than triple increase in thermal conductivity.…”

Section: Introductionmentioning

confidence: 99%

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Studying thermal conductivity of magnetic nanofluids in constant magnetic field

et al. 2017

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Abstract. The thermal conductivity of magnetic nanofluids in a constant magnetic field is investigated. The concentration dependence of the thermal conductivity coefficient of magnetic fluids based on water and iron oxide nanoparticles Fe 3 O 4 in a constant magnetic field is obtained. The dependence of the thermal conductivity coefficient of nanofluid on the nanoparticles size in a magnetic field is obtained. The temperature effect on the thermal conductivity of magnetic nanofluid in a constant magnetic field is studied.

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Section: Sts-33mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Studying thermal conductivity of magnetic nanofluids in constant magnetic field

et al. 2017

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“…It is worth to mention that some advances have been made in this direction with magnetic fluids, as their thermal properties can be controlled with the concentration of particles and the application of magnetic fields with different strengths. In this kind of fluids, it has been observed that the development of chains by the embedded particles greatly enhances their thermal conductivity in the direction of the chains [8,9,10,11,12].…”

Section: Introductionmentioning

confidence: 99%

Thermal properties of composite two-layer systems with a fractal inclusion structure

Reyes-Salgado¹,

Dossetti²,

Bonilla-Capilla³

et al. 2014

J. Phys. D: Appl. Phys.

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Abstract. In this work, we study the thermal transport properties of platelike composite two-layer samples made of polyester resin and magnetite inclusions. By means of photoacoustic spectroscopy and thermal relaxation, their effective thermal diffusivity and conductivity were experimentally measured. The composite layers were prepared under the action of a static magnetic field, resulting in anisotropic inclusion structures with the formation of chains of magnetite particles parallel to the faces of the layers. In one kind of bilayers, a composite layer was formed on top of a resin layer while their relative thickness was varied. These samples can be described by known models. In contrast, bilayers with the same concentration of inclusions and the same thickness on both sides, where only the angle between their inclusion structures was systematically varied, show a nontrivial behaviour of their thermal conductivity as a function of this angle. Through a lacunarity analysis, we explain the observed thermal response in terms of the complexity of the interface between the layers.

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“…7 Formation of these structures, in particular, ordered chains or columnar structures in ferrofluids as a result of an applied field, leads to a change in the macroscopic properties of the medium, 8,9 while thermodynamic properties such as effective heat capacity remain unaffected by these heterogeneous structures. 10 For instance, magnetization of ferrofluid increases with the growth of chains, 2,11-14 viscosity abruptly increases, 1,2,15 thermal conductivity is enhanced if the field direction is parallel to temperature gradient, [16][17][18][19][20] and optical properties become strongly anisotropic. 1,[21][22][23] There are several examples of successful and prospective applications of self-assembled or field-assisted magnetic nanoparticles from technical applications to medical ones: in data storage, electronic devices, sensors, rotating shaft seals, hydrostatic and hydrodynamic bearings, magnetoacoustic transducers, vibration isolation and inertia damping systems, thermal systems, medical diagnostics, therapy and drug delivery, biophysical studies, and magnetic biosensing.…”

Section: Introductionmentioning

confidence: 99%

Direct observations of field-induced assemblies in magnetite ferrofluids

Mousavi

Khapli

Kumar

2015

Journal of Applied Physics

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Evolution of microstructures in magnetite-based ferrofluids with weak dipolar moments (particle size 10 nm) is studied with an emphasis on examining the effects of particle concentration (/) and magnetic field strength (H) on the structures. Nanoparticles are dispersed in water at three different concentrations, / ¼ 0.15%, 0.48%, and 0.59% (w/v) [g/ml%] and exposed to uniform magnetic fields in the range of H ¼ 0.05-0.42 T. Cryogenic transmission electron microscopy is employed to provide in-situ observations of the field-induced assemblies in such systems. As the magnetic field increases, the Brownian colloids are observed to form randomly distributed chains aligned in the field direction, followed by head-to-tail chain aggregation and then lateral aggregation of chains termed as zippering. By increasing the field in low concentration samples, the number of chains increases, though their length does not change dramatically. Increasing concentration increases the length of the linear particle assemblies in the presence of a fixed external magnetic field. Thickening of the chains due to zippering is observed at relatively high fields. Through a systematic variation of concentration and magnetic field strength, this study shows that both magnetic field strength and change in concentration can strongly influence formation of microstructures even in weak dipolar systems. Additionally, the results of two commonly used support films on electron microscopy grids, continuous carbon and holey carbon films, are compared. Holey carbon film allows us to create local regions of high concentrations that further assist the development of field-induced assemblies. The experimental observations provide a validation of the zippering effect and can be utilized in the development of models for thermophysical properties such as thermal conductivity. V C 2015 AIP Publishing LLC.

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The thermal conductivity of water base ferrofluids under magnetic field

Cited by 180 publications

References 22 publications

Studying thermal conductivity of magnetic nanofluids in constant magnetic field

Studying thermal conductivity of magnetic nanofluids in constant magnetic field

Thermal properties of composite two-layer systems with a fractal inclusion structure

Direct observations of field-induced assemblies in magnetite ferrofluids

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