Heat transfer studies in thermally conducting and electrically insulating nano-oils in a natural circulation loop

Manu Mohan, Shijo Thomas, J. Taha-Tijerina, T. N. Narayanan, C. B. Sobhan, P. M. Ajayan

Research output: Contribution to conferencePaper

4 Citations (Scopus)

Abstract

Mineral oil (MO), a dielectric insulating fluid, is commonly used as coolant and lubricant in various applications, such as in high voltage power transmission systems and machinery. The mode of heat transfer in most of these systems is natural convection. Prolonged operation at higher temperatures leads to the degradation of the dielectric coolant, which leads to diverse problems, such as shortage or breakdown of these devices and apparatuses. Increasing the heat transfer capability of the insulating fluid will minimize the energy consumption of the system, prolonging its useful life. It is proposed to improve the heat transfer performance of insulating fluid by the addition of hexagonal boron nitride (h-BN), which is synthesized and finally obtained in 2D-nanosheets through wet exfoliation technique, without affecting its electrical insulating property. h-BN was reported to have superb effect on thermal conductivity of MO (∼ 80% increase at 0.10wt.%) on addition at very low filler fraction [1], thermal stability of up to 800°C [2], and good electrical insulating properties due to its nature (electron band gap of approx. 4.5eV). The present work reports the application of nano-oil (MO + h-BN 2D-nanosheets) for enhanced heat dissipation. A rectangular thermosyphon loop was modeled as the thermal system in transformer. The aspect ratio of the loop and the positions of the heater and cooler were chosen according to the stability criterion so that the flow remains stable and unidirectional throughout the experiment. The effect on heat removal by varying the concentration of h-BN 2D-nanosheets (h-BNNS) in MO was measured and discussed. Copyright © 2013 by ASME.
Original languageEnglish
DOIs
Publication statusPublished - 1 Jan 2013
Externally publishedYes
EventASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) -
Duration: 1 Jan 2013 → …

Conference

ConferenceASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE)
Period1/1/13 → …

Fingerprint

Boron nitride
Mineral oils
Nanosheets
Heat transfer
Coolants
Fluids
Thermosyphons
Stability criteria
Power transmission
Heat losses
Natural convection
Machinery
Lubricants
Fillers
Aspect ratio
Thermal conductivity
Energy gap
Thermodynamic stability
Energy utilization
Degradation

Cite this

Mohan, M., Thomas, S., Taha-Tijerina, J., Narayanan, T. N., Sobhan, C. B., & Ajayan, P. M. (2013). Heat transfer studies in thermally conducting and electrically insulating nano-oils in a natural circulation loop. Paper presented at ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), . https://doi.org/10.1115/IMECE2013-64285
Mohan, Manu ; Thomas, Shijo ; Taha-Tijerina, J. ; Narayanan, T. N. ; Sobhan, C. B. ; Ajayan, P. M. / Heat transfer studies in thermally conducting and electrically insulating nano-oils in a natural circulation loop. Paper presented at ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), .
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abstract = "Mineral oil (MO), a dielectric insulating fluid, is commonly used as coolant and lubricant in various applications, such as in high voltage power transmission systems and machinery. The mode of heat transfer in most of these systems is natural convection. Prolonged operation at higher temperatures leads to the degradation of the dielectric coolant, which leads to diverse problems, such as shortage or breakdown of these devices and apparatuses. Increasing the heat transfer capability of the insulating fluid will minimize the energy consumption of the system, prolonging its useful life. It is proposed to improve the heat transfer performance of insulating fluid by the addition of hexagonal boron nitride (h-BN), which is synthesized and finally obtained in 2D-nanosheets through wet exfoliation technique, without affecting its electrical insulating property. h-BN was reported to have superb effect on thermal conductivity of MO (∼ 80{\%} increase at 0.10wt.{\%}) on addition at very low filler fraction [1], thermal stability of up to 800°C [2], and good electrical insulating properties due to its nature (electron band gap of approx. 4.5eV). The present work reports the application of nano-oil (MO + h-BN 2D-nanosheets) for enhanced heat dissipation. A rectangular thermosyphon loop was modeled as the thermal system in transformer. The aspect ratio of the loop and the positions of the heater and cooler were chosen according to the stability criterion so that the flow remains stable and unidirectional throughout the experiment. The effect on heat removal by varying the concentration of h-BN 2D-nanosheets (h-BNNS) in MO was measured and discussed. Copyright {\circledC} 2013 by ASME.",
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Mohan, M, Thomas, S, Taha-Tijerina, J, Narayanan, TN, Sobhan, CB & Ajayan, PM 2013, 'Heat transfer studies in thermally conducting and electrically insulating nano-oils in a natural circulation loop' Paper presented at ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 1/1/13, . https://doi.org/10.1115/IMECE2013-64285

Heat transfer studies in thermally conducting and electrically insulating nano-oils in a natural circulation loop. / Mohan, Manu; Thomas, Shijo; Taha-Tijerina, J.; Narayanan, T. N.; Sobhan, C. B.; Ajayan, P. M.

2013. Paper presented at ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), .

Research output: Contribution to conferencePaper

TY - CONF

T1 - Heat transfer studies in thermally conducting and electrically insulating nano-oils in a natural circulation loop

AU - Mohan, Manu

AU - Thomas, Shijo

AU - Taha-Tijerina, J.

AU - Narayanan, T. N.

AU - Sobhan, C. B.

AU - Ajayan, P. M.

PY - 2013/1/1

Y1 - 2013/1/1

N2 - Mineral oil (MO), a dielectric insulating fluid, is commonly used as coolant and lubricant in various applications, such as in high voltage power transmission systems and machinery. The mode of heat transfer in most of these systems is natural convection. Prolonged operation at higher temperatures leads to the degradation of the dielectric coolant, which leads to diverse problems, such as shortage or breakdown of these devices and apparatuses. Increasing the heat transfer capability of the insulating fluid will minimize the energy consumption of the system, prolonging its useful life. It is proposed to improve the heat transfer performance of insulating fluid by the addition of hexagonal boron nitride (h-BN), which is synthesized and finally obtained in 2D-nanosheets through wet exfoliation technique, without affecting its electrical insulating property. h-BN was reported to have superb effect on thermal conductivity of MO (∼ 80% increase at 0.10wt.%) on addition at very low filler fraction [1], thermal stability of up to 800°C [2], and good electrical insulating properties due to its nature (electron band gap of approx. 4.5eV). The present work reports the application of nano-oil (MO + h-BN 2D-nanosheets) for enhanced heat dissipation. A rectangular thermosyphon loop was modeled as the thermal system in transformer. The aspect ratio of the loop and the positions of the heater and cooler were chosen according to the stability criterion so that the flow remains stable and unidirectional throughout the experiment. The effect on heat removal by varying the concentration of h-BN 2D-nanosheets (h-BNNS) in MO was measured and discussed. Copyright © 2013 by ASME.

AB - Mineral oil (MO), a dielectric insulating fluid, is commonly used as coolant and lubricant in various applications, such as in high voltage power transmission systems and machinery. The mode of heat transfer in most of these systems is natural convection. Prolonged operation at higher temperatures leads to the degradation of the dielectric coolant, which leads to diverse problems, such as shortage or breakdown of these devices and apparatuses. Increasing the heat transfer capability of the insulating fluid will minimize the energy consumption of the system, prolonging its useful life. It is proposed to improve the heat transfer performance of insulating fluid by the addition of hexagonal boron nitride (h-BN), which is synthesized and finally obtained in 2D-nanosheets through wet exfoliation technique, without affecting its electrical insulating property. h-BN was reported to have superb effect on thermal conductivity of MO (∼ 80% increase at 0.10wt.%) on addition at very low filler fraction [1], thermal stability of up to 800°C [2], and good electrical insulating properties due to its nature (electron band gap of approx. 4.5eV). The present work reports the application of nano-oil (MO + h-BN 2D-nanosheets) for enhanced heat dissipation. A rectangular thermosyphon loop was modeled as the thermal system in transformer. The aspect ratio of the loop and the positions of the heater and cooler were chosen according to the stability criterion so that the flow remains stable and unidirectional throughout the experiment. The effect on heat removal by varying the concentration of h-BN 2D-nanosheets (h-BNNS) in MO was measured and discussed. Copyright © 2013 by ASME.

U2 - 10.1115/IMECE2013-64285

DO - 10.1115/IMECE2013-64285

M3 - Paper

ER -

Mohan M, Thomas S, Taha-Tijerina J, Narayanan TN, Sobhan CB, Ajayan PM. Heat transfer studies in thermally conducting and electrically insulating nano-oils in a natural circulation loop. 2013. Paper presented at ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), . https://doi.org/10.1115/IMECE2013-64285