Thermal conductivity of a diamond magnetite composite fluid under the effect of a uniform magnetic field
Introduction
One of the great challenges in materials science is to devise working materials whose thermal properties can be tuned at will in a certain range. This is hard to achieve with homogeneous materials; however, this objective could be reached when working with composites [1], [2].
In particular, electronics, computing and systems for energy saving and generation are among the most demanding and require the development of flexible and versatile composites which confront the challenges of controlling the dissipation of heat, not only at the micro- but also at large scale [3]. New kinds of materials are needed in order to solve the increasing demands in diverse applications. An innovative way of improving the thermal conductivities of working media is to suspend ultrafine metallic or nonmetallic solid powders in traditional fluids, taking into account that the thermal conductivities of most solid materials are higher than those of liquids [4], [5], [6]. Those kinds of materials can exploit the physical properties of the liquids, which are their high heat capacity, the tendency to take the form of the system of interest, and those that can be a good option when a suitable thermal contact is desirable.
Among the most promising composite materials are smart fluids, which are those whose properties can be changed by applying external stimuli (electric or magnetic fields, heat, mechanical force, light, etc.) [7], [8]. Ferrofluids are colloidal stable suspension of ferromagnetic particles of tenths of nanometers in a liquid carrier. The nanoparticles are coated with adsorbed surfactant layers to keep the suspension state stable. In the absence of magnetic field, the particles are randomly oriented and the fluid has no net magnetization. However, in the presence of an external magnetic field, the magnetic nanoparticles become aligned in the direction of the field, and thus forming chain-like structures [9], [10], [11]. The analysis of the thermal properties and the viscosity of ferrofluids among other features have attracted greatest attention of diverse research groups in the last years [12], [13], [14], [15], [16]. On the other hand, it is well known that diamond has excellent physical properties. Its thermal conductivity is higher than any of the metals, and offers a wide variety of applications when large heat transfer rates are required [17], [18].
In this work, the ability of a magnetic field to induce the formation of chain-like structures in a suspension of a non-magnetic diamond microparticles in a carrier ferrofluid, called negative magnetophoresis [19], [20], is used to control heat transport. The thermal analysis of the samples was performed using the thermal wave resonator cavity (TWRC), which has become, in the last few years, an attractive technique, in the thermal characterization of liquids and gases, due to its simplicity, versatility and accuracy [21], [22], [23]. This technique provided the thermal diffusivity of the samples, which is the physical property that measures how fast a material is heated or cooled, and rules the heat transfer under dynamic conditions. Additionally, the thermal wave cavity has been successfully used to study heat transfer in mixtures of liquids [24]. In this work we are going farther proposing to use the TWRC to measure stable mixtures of solid particles in liquids under the influence of magnetic fields.
Section snippets
Preparation of samples
Diamond microparticles with a Gaussian size distribution with 3.2 μm mean diameter and standard deviation of 0.6 μm were purchased from Diamond Tech Quality; and ferrofluid (Ferrotec EMG 900 @ 3% magnetite volume fraction, Gaussian particle size distribution with 10 nm mean diameter and standard deviation of 1 nm) was used to obtain the samples. The fluids were prepared by a one-step technique, which consists in the mixing of the diamond microparticles with the ferrofluid matrix, at different
Results and discussion
Samples of ferrofluid at different volume concentrations of diamond particles were obtained. To examine the formation of chain-like structures, a sample of a low diamond concentration (1% diamond particles and 3% of magnetite) under a magnetic field was observed with the use of a microscope objective (50 × Edmund Optics, #59-881) mounted into a digital camera; images are shown in Fig. 6. For the case of nonmagnetic particles suspended in a magnetic carrier fluid there is an arrangement to form
Conclusions
The usefulness of the negative magnetophoresis phenomena to develop magnetically sensitive smart fluids to control its thermal conductivity is shown. In particular when the magnetic field is parallel to the heat flux, a thermal conductivity enhancement is observed in comparison with the case in which the magnetic field has been turned off. The thermal conductivity enhancement shows a strong dependence on the diamond volume fraction, showing a maximum enhancement of 76% when the diamond
Prime novelty statement
We found a complex thermal behavior for a diamond-magnetite composite fluid under the effect of a magnetic filed. An important thermal conductivity enhancement is observed when the field is applied due to a tridimensional chain-like structuring formed by the diamond particles in the direction of the field, which promotes an easy thermal transport over these high thermal conductivity roads.
Additionally the thermal conductivity of the material could be controlled in a switchable way and moreover
Acknowledgments
R. A. Medina-Esquivel acknowledges support from the Secretariat of Public Education and Council on Science and Technology (SEP-CONACYT) under Grant No. 135131. M. A. Zambrano-Arjona acknowledges support from the SEP-CONACYT under Grant No. 182982.
References (42)
- et al.
Heat transfer enhancement of nanofluids
Int. J. Heat Fluid Flow
(2000) On the Lewis–Nielsen model for thermal/electrical conductivity of composites
Compos. A: Appl. Sci. Manuf.
(2008)- et al.
Magnetorheology of ferrofluid composites
J. Magn. Magn. Mater.
(1995) - et al.
Fabrication, characterization and measurement of thermal conductivity of Fe3O4 nanofluids
J. Magn. Magn. Mater.
(2010) - et al.
Experimental investigations on transport properties of magnetic fluids
Exp. Thermal Fluid Sci.
(2005) - et al.
The thermal conductivity of water base ferrofluids under magnetic field
Exp. Thermal Fluid Sci.
(2012) - et al.
Detonation synthesized nanodiamond powder for the preparation of porous polycrystalline micron powders
Diam. Relat. Mater.
(2008) - et al.
Nanofluid with tunable thermal properties
Appl. Phys. Lett.
(2008) - et al.
Anomalous thermal conductivity enhancement in nanotube suspensions
Appl. Phys. Lett.
(2001) - et al.
Effects of various parameters on nanofluid thermal conductivity
J. Heat Transf.
(2006)
Discussion on the thermal conductivity enhancement of nanofluids
Nanoscale Res. Lett.
Nanofluids: Science and Technology
Adaptronics and Smart Structures: Basics, Materials, Design, and Applications
Magnetic fluids suspensions of magnetic dipoles and their magnetic control
J. Phys. Condens. Matter
Field-induced transmission of light in ionic ferrofluids of tunable viscosity
J. Phys. D. Appl. Phys.
Thermal conductivity measurements on ferrofluids
Colloid Polym. Sci.
Enhancement of thermal conductivity in magnetite based nanofluid due to chainlike structures
Appl. Phys. Lett.
Effect of Diamond Nanolubricant on R134a Pool Boiling Heat Transfer With Extensive Measurement and Analysis Details
Nanodiamond nanofluids for enhanced thermal conductivity
ACS Nano
Formation of ordered cellular structures in suspension via label-free negative magnetophoresis
Nano Lett.
On-chip free-flow magnetophoresis: continuous flow separation of magnetic particles and agglomerates
Anal. Chem.
Cited by (12)
Thermal and rheological properties of magnetic nanofluids: Recent advances and future directions
2022, Advances in Colloid and Interface ScienceCitation Excerpt :The experimental results showed an increase in thermal conductivity with an increase in volume fraction and magnetic field before reaching a saturation point. Medina-Esquivel et al. [82] studied the thermal conductivity of a diamond magnetite composite fluid under the effect of a uniform magnetic field. The enhanced thermal conductivity observed under a magnetic field was attributed to the effective heat propagation through a chain-like structures formed by the diamond particles in the direction of the field.
Unique rheological behavior of detonation nanodiamond hydrosols: The nature of sol-gel transition
2020, CarbonCitation Excerpt :The reason is formation of sp2 layer on the surface of DND particles, which probably screened electrostatic interaction. The rheological study of DND hydrosols is of great importance for numerous possible applications in biomedicine [13], development of novel liquid heat carriers [14,15] and magnetic liquids [16]. The DND hydrosol was prepared by a method described previously [9].
Impact of field ramp rate on magnetic field assisted thermal transport in ferrofluids
2020, Journal of Molecular LiquidsCitation Excerpt :Another direction pursued to improve thermal conductivity of ferrofluids is the incorporation of additives. Some of the additives that were reported in recent years to improve thermal conductivity of ferrofluid suspensions are copper oxide [35], silver nanowire [36], diamond microparticles [37], carbon nanofibers [38] etc. Primary and secondary layers of surfactant was also reported to influence thermal transport in ferrofluids where the former gave lower thermal conductivity in the absence of field while in the presence of magnetic field thermal transport was found to be higher for the system with only a primary layer of surfactant [39].
Investigation of convective heat transfer of ferrofluid using CFD simulation and adaptive neuro-fuzzy inference system optimized with particle swarm optimization algorithm
2018, Powder TechnologyCitation Excerpt :Nkurikiyimfura et al. [22] showed that the thermal conductivity (TC) increased fast with the growing of magnetic field intensity in the case of the parallel magnetic field, but it decreased in a perpendicular case. Medina-Esquivel et al. [23] investigated the thermal conductivity of the ferrofluids with immersed diamond micro-particles. They found out that TC had a maximum enhancement of 76% under the parallel magnetic field.