Applications of Ferro-Nanofluid on a Micro-Transformer

Tsai, Tsung-Han; Kuo, Long-Sheng; Chen, Ping‐Hei; Lee, Dasheng; Yang, Chih-Chao

doi:10.3390/s100908161

Cited by 42 publications

(37 citation statements)

References 22 publications

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“…The rear ends of surfactant molecules rebuff each other to ensure a distance between the particles to hinder them from agglomeration. Surface modification of NPs is an efficient method to avert NPs agglomeration in insulating liquids [49][50][51][52]. Nevertheless, the surface modifiers used for mineral oils cannot be used with other carrier oils, such as vegetable oils, because of different molecular forms/structures.…”

Section: (A) Materials Selection For Experimentsmentioning

confidence: 99%

Study of Dielectric Breakdown Performance of Transformer Oil Based Magnetic Nanofluids

Rafiq

et al. 2017

Energies

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Abstract:Research on the transformer oil-based nanofluids (NFs) has been raised expeditiously over the past decade. Although, there is discrepancy in the stated results and inadequate understanding of the mechanisms of improvement of dielectric nanofluids, these nanofluids have emerged as a potential substitute of mineral oils as insulating and heat removal fluids for high voltage equipment. The transformer oil (TO) based magnetic fluids (ferrofluids) may be regarded as the posterity insulation fluids as they propose inspiring unique prospectus to improve dielectric breakdown strength, as well as heat transfer efficiency, as compared to pure transformer oils. In this work, transformer oil-based magnetic nanofluids (MNFs) are prepared by dispersal of Fe 3 O 4 nanoparticles (MNPs) into mineral oil as base oil, with various NPs loading from 5 to 80% w/v. The lightning impulse breakdown voltages (BDV) measurement was conducted in accordance with IEC 60897 by using needle to sphere electrodes geometry. The test results showed that dispersion of magnetic NPs may improve the insulation strength of MO. With the increment of NPs concentrations, the positive lightning impulse (LI) breakdown strength of TO is first raised, up to the highest value at 40% loading, and then tends to decrease at higher concentrations. The outcomes of negative LI breakdown showed that BDV of MNFs, with numerous loadings, were inferior to the breakdown strength of pure MO. The 40% concentration of nanoparticles (optimum concentration) was selected, and positive and negative LI breakdown strength was also further studied at different sizes (10 nm, 20 nm, 30 nm and 40 nm) of NPs and different electrode gap distances. Augmentation in the BDV of the ferrofluids (FFs) is primarily because of dielectric and magnetic features of Fe 3 O 4 nanoaprticles, which act as electron scavengers and decrease the rate of free electrons produced in the ionization process. Research challenges and technical difficulties associated with ferrofluids for practical applications are mentioned. The advantages and disadvantages linked with magnetic fluids are also presented.

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Section: (A) Materials Selection For Experimentsmentioning

confidence: 99%

Study of Dielectric Breakdown Performance of Transformer Oil Based Magnetic Nanofluids

Rafiq

et al. 2017

Energies

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“…The critical heat flux (CHF) is a process of vigorous heat transfer that occurs with a phase change from liquid to vapor in a pool of initially quiescent liquid. Various NFs have been investigated to date to enhance the CHF, and include those made with Al 2 O 3 , TiO 2 , ZnO 2 , CuO, Fe 3 O 4 , and carbon materials [10,11]. However, these materials have significant drawbacks that include high volume concentrations, relatively short shelf-life, environmental unfriendliness, oxidation/reduction of the NPs during pool boiling and high cost.…”

mentioning

confidence: 99%

Highly wettable CuO:graphene oxide core-shell porous nanocomposites for enhanced critical heat flux

Cheedarala

Park

2015

Phys. Status Solidi A

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Copper oxide nanoparticles nanofluids (CuO-NPs-NF) are promising candidates for pool boiling critical heat flux (CHF) applications due to their multifaceted advantages like easy tunability, eco-friendliness, cost-effectiveness, easy chemical modification and higher thermal conductivities. In addition, entrapping the CuO-NPs in/on to graphene oxide (GO) improves the CHF values compared to CuO-NPs alone. This paper reports a high performance hybrid NFs based on CuO and GO nanocomposites (CuO:GO-NCs-NFs), exhibiting higher pool boiling CHF values even at very low concentrations. The proposed novel NFs have higher thermal conductivities compared with the DI water. The 0.06 wt% CuO:GO-NCs-NF shows the highest CHF value, ca.160%, which is much higher than that of pure CuO-NPs-NF (99%). Atomic force microscope (AFM) and field-emission SEM (FE-SEM) micrographs of the wire after the pool boiling experiments revealed a rough surface having high wettability and lower contact angle (CA) with 478 due to the formation of a layer-on-layer network on the wire surface. In addition, we have developed a method for in situ generation of core-shell template model CuO-NPs using Ostwald's ripening method in isopropanol-water system. Eventually, the CuO:GO-NCs-NF could show robust and high performance CHF pool boiling even at low concentrations that are required in realistic applications.

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“…Besides the well-known application of ferrofluids in sealing and lubrication, recent developments envisaged their potential in fields like actuation [22,23], medicine [1,16], biotechnology [14,24], as cooling fluids [25][26][27][28][29] or as liquid core in power transformers [30,31]. The applications in medicine and biotechnology require from the magnetic nanofluid to be biocompatible.…”

Section: Introductionmentioning

confidence: 99%

Nanofluid with Colloidal Magnetic Fe3O4 Nanoparticles and Its Applications in Electrical Engineering

Pîslaru‐Dănescu¹,

Ţelipan²,

Stoian³

et al. 2017

Nanofluid Heat and Mass Transfer in Engineering Problems

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In this study, we propose a new type of a cooling agent based on magnetic nanofluid for the purpose of replacing the classical cooling fluids in electrical power transformers. The magnetite (Fe 3 O 4 ) nanoparticles were synthesized by the co-precipitation method from an aqueous medium of salts FeCl 3 x6H 2 O and FeSO 4 x7H 2 O in the molar ratio Fe 3+ /Fe 2+ = 2:1, by alkalization with 10% aqueous solution of NaOH at 80°C, for 1 h. The size of the magnetite nanoparticles, as measured by X-ray diffraction method, was 14 nm and by scanning electron microscopy (SEM), they are between 10 and 30 nm. Magnetite powder was placed in oleic acid as a surfactant to prevent agglomeration of nanoparticles. The resulting mixture was dispersed in transformer oil UTR 40, with the role of carrier liquid. The magnetic, rheological, thermal and electrical characteristic properties of the obtained Fe 3 O 4 transformer oil-based nanofluid were determined. A mathematical model and numerical simulation results are very useful for investigating the heat transfer performances of the magnetic nanofluid. Based on this study, it was tested the cooling performance of this magnetic nanofluid for two types of electrical power transformers as compared to classical methods. We also presented a microactuator based on the same magnetic nanofluid.

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Applications of Ferro-Nanofluid on a Micro-Transformer

Cited by 42 publications

References 22 publications

Study of Dielectric Breakdown Performance of Transformer Oil Based Magnetic Nanofluids

Study of Dielectric Breakdown Performance of Transformer Oil Based Magnetic Nanofluids

Highly wettable CuO:graphene oxide core-shell porous nanocomposites for enhanced critical heat flux

Nanofluid with Colloidal Magnetic Fe3O4 Nanoparticles and Its Applications in Electrical Engineering

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