Suspended nanoparticles as a way to improve thermal energy transfer efficiency

Witharana, Sanjeeva; Weliwita, J. A.

doi:10.1109/iciafs.2012.6419922

Cited by 2 publications

(2 citation statements)

References 16 publications

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“…Similar results were obtained in other studies with other base fluids such as water or ethylene-glycol, which showed improved conductivity [ 172 , 173 , 175 , 176 , 179 , 183 ] and convection coefficients [ 173 ] as the concentration of particles increased. These results were dependent on the composition [ 27 , 175 ], shape [ 142 , 183 ], and size [ 173 , 176 ] of the nanoparticles.…”

Section: Achievements Found In Literaturesupporting

confidence: 89%

Mineral and Ester Nanofluids as Dielectric Cooling Liquid for Power Transformers

et al. 2022

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Amidst the new techniques facing the improvement of cooling and insulating efficiency and the design of electric transformers, constrained by the current technologies, one of the more promising is the substitution of traditional dielectric oils for nanofluids. Research on nanofluids for their application in transformers as a coolant and dielectric medium have been performed during the last two decades and continue today. This review tries to collect and analyze the available information in this field and to offer it already dissected to researchers, focusing on the preparation methods and how nanoparticles affect the main properties of the base fluids. Here we also addressed the influence of different parameters as particle characteristics or environmental conditions in nanofluids performance, the evolution with time of the measured properties, or the neighboring relationship of nanofluids with other transformer components. In this sense, the most reviewed articles reflect enhancements of thermal conductivity or dielectric strength, as well as an improvement of time evolution of these properties, with respect to those that are found in base fluids, and, also, a better interaction between these nanofluids and dielectric cellulosics. Thus, the use of dielectric nanofluids in transformers may allow these machines to work safer or over their design parameters, reducing the risk of failure of the electrical networks and enhancing their life expectancy. Nevertheless, these advantages will not be useful unless a proper stability of nanofluids is ensured, which is achieved in a small part of revised articles. A compendium of the preparation methodology with this aim is proposed, to be checked in future works.

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Section: Achievements Found In Literaturesupporting

confidence: 89%

Mineral and Ester Nanofluids as Dielectric Cooling Liquid for Power Transformers

et al. 2022

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“…The calculations are performed for suspensions of alumina spherical nanoparticles in water, ethylene glycol and a 50/50 w% water/ethylene-glycol mixture, respectively. The theory is of course by no means limited to these fluids which have been selected because they allow a direct comparison with experimental data [19,[56][57][58][59][60][61]. The material properties of alumina used for the calculations are given in Table 1 and refer to the room temperature (taken here to be 300 K).…”

Section: Numerical Results and Discussionmentioning

confidence: 99%

The role of several heat transfer mechanisms on the enhancement of thermal conductivity in nanofluids

Machrafi

Lebon

2016

Continuum Mech. Thermodyn.

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A modelling of the thermal conductivity of nanofluids based on extended irreversible thermodynamics is proposed with emphasis on the role of several coupled heat transfer mechanisms: liquid interfacial layering between nanoparticles and base fluid, particles agglomeration and Brownian motion. The relative importance of each specific mechanism on the enhancement of the effective thermal conductivity is examined. It is shown that sizes of the nanoparticles and the liquid boundary layer around the particles play a determining role. For nanoparticles close to molecular range, the Brownian effect is important. At nanoparticles of the order of 1-100 nm, both agglomeration and liquid layering are influent. Agglomeration becomes the most important mechanism at nanoparticle sizes of the order of 100 nm and higher.The theoretical considerations are illustrated by three case-studies: suspensions of alumina rigid spherical nanoparticles in water, ethylene glycol and a 50/50 w% water/ethylene-glycol mixture, respectively, good agreement with experimental data is observed.

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Suspended nanoparticles as a way to improve thermal energy transfer efficiency

Cited by 2 publications

References 16 publications

Mineral and Ester Nanofluids as Dielectric Cooling Liquid for Power Transformers

Mineral and Ester Nanofluids as Dielectric Cooling Liquid for Power Transformers

The role of several heat transfer mechanisms on the enhancement of thermal conductivity in nanofluids

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