The effect of nanoparticle surfactant polarization on trapping depth of vegetable insulating oil-based nanofluids

Li, Jian; Du, Bin; Wang, Feipeng; Yao, Wei; Yao, Shuhan

doi:10.1016/j.physleta.2015.12.008

Cited by 47 publications

(50 citation statements)

References 12 publications

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“…Furthermore, since C 60 and silane-coated ZnO NPs are hydrophobic [21,35], water adsorption cannot explain the increments in streamer inception voltages reported in Figures 10 and 11. These findings indicate that NPs influence the positive streamer inception process by other physical mechanism(s) in addition to water adsorption.…”

Section: Water Adsorption Hypothesismentioning

confidence: 93%

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Streamer Inception from Ultra-Sharp Needles in Mineral Oil Based Nanofluids

2018

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Positive and negative streamer inception voltages from ultra-sharp needle tips (with tip radii below 0.5 µm) are measured in TiO 2 , SiO 2 , Al 2 O 3 , ZnO and C 60 nanofluids. The experiments are performed at several concentrations of nanoparticles dispersed in mineral oil. It is found that nanoparticles influence positive and negative streamers in different ways. TiO 2 , SiO 2 and Al 2 O 3 nanoparticles increase the positive streamer inception voltage only, whilst ZnO and C 60 nanoparticles augment the streamer inception voltages in both polarities. Using these results, the main hypotheses explaining the improvement in the dielectric strength of the host oil due to the presence of nanoparticles are analyzed. It is found that the water adsorption hypothesis of nanoparticles is consistent with the increments in the reported positive streamer inception voltages. It is also shown that the hypothesis of nanoparticles reducing the electron velocity by hopping transport mechanisms fails to explain the results obtained for negative streamers. Finally, the hypothesis of nanoparticles attaching electrons according to their charging characteristics is found to be consistent with the results hereby presented on negative streamers.

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Section: Water Adsorption Hypothesismentioning

confidence: 93%

“…Similarly, the NPs chosen range from highly hydrophilic to highly hydrophobic in order to discuss the water absorption hypothesis [16]. Five different NPs are used: laboratory-grade zinc oxide (ZnO-C 18 ) silane-coated NPs [21] and commercial-grade NPs of aluminum…”

Section: Preparation Of Nanofluidsmentioning

confidence: 99%

Streamer Inception from Ultra-Sharp Needles in Mineral Oil Based Nanofluids

2018

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“…These polarized charges generated the electric field, which changed the original electric field. A "trapping" was formed near the nanoparticles, thereby enhancing the breakdown voltage [28].…”

Section: Dielectric Propertiesmentioning

confidence: 99%

Enhanced Electrical Insulation and Heat Transfer Performance of Vegetable Oil Based Nanofluids

Yao

Huang

et al. 2018

Journal of Nanomaterials

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Nanoparticles enhance the electrical insulation and thermal properties of vegetable oil, and such improvements are desirable for its application as an alternative to traditional insulating oil for power transformers. However, the traditional method of insulating nanofluids typically achieves high electrical insulation but low thermal conductivity. This work reports an environmentally friendly vegetable oil using exfoliated hexagonal boron nitride (h-BN) showing high thermal conductivity and high electrical insulation. Stable nanofluids were prepared by liquid exfoliation of h-BN in isopropyl alcohol. With 0.1 vol.% of the nano-oil, the AC breakdown voltage increased by 18% at 25 ∘ C and 15% at 90 ∘ C. Both the positive and negative lightning impulse breakdown voltages of the nanooil were also enhanced compared with those of the pure oil. Moreover, the thermal conductivity of the nano-oil increased by 11.9% at 25 ∘ C and 14% at 90 ∘ C. Given its high thermal conductivity, the nano-oil exhibited faster heating and cooling effects than the pure oil. Nano-oils with an electric field (either DC or AC) displayed a faster thermal response than that without an electric field. The reason is that h-BN is oriented under the electric field and formed a thermal network to increase the heat transfer.

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“…Similar morphology-dependent optical, surface plasmons, catalytic activity and electrical behaviors are seen in literatures. [37][38][39] The dielectric constant of CdO morphotypes as a function of temperature at 55 Hz and 100 kHz are shown in Figs. 3(III) and 3(IV), respectively.…”

Section: Dielectric Polarization and Relaxationmentioning

confidence: 99%

Morphology-dependent space charge polarization and dielectric relaxation of CdO nanomorphotypes

Thomas¹,

Abraham²

2016

J. Adv. Dielect.

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A versatile approach signifying the morphology-dependent dielectric polarization and relaxation mechanisms of cadmium oxide (CdO) nanosphere, nanoflakes and nanoparallelepiped morphotypes as a function of frequency and temperature is presented. Variation of dielectric property is observed due to the changes of space charge/interfacial polarization resulting from the variations of surface to volume ratio of nanomorphology. Accordingly, colossal dielectric constant value has been observed in CdO nanosphere having larger surface to volume ratio. The order of dielectric constant (dc) values observed for the present nanomorphologies is: dc of sphere > dc of flakes > dc of parallelepiped resembles the order of surface to volume ratios of the present morphologies respectively. The experimental data of complex impedance values are numerically fitted using theoretical models which provide the information of role of grain resistance on dielectric polarization and Cole-Cole type mechanism of dielectric relaxation process. The activation energies for electron transport are found to be 0.087 eV for spheres, 0.074 eV for flakes and 0.067 for parallelepiped nanomorphotypes of CdO. The dielectric and impedance spectroscopic analysis of the present material opens up wide scope for morphology-dependent tuning of nanomaterials for electrical applications.

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The effect of nanoparticle surfactant polarization on trapping depth of vegetable insulating oil-based nanofluids

Cited by 47 publications

References 12 publications

Streamer Inception from Ultra-Sharp Needles in Mineral Oil Based Nanofluids

Streamer Inception from Ultra-Sharp Needles in Mineral Oil Based Nanofluids

Enhanced Electrical Insulation and Heat Transfer Performance of Vegetable Oil Based Nanofluids

Morphology-dependent space charge polarization and dielectric relaxation of CdO nanomorphotypes

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