Details
| Original language | English |
|---|---|
| Article number | 104344 |
| Journal | International Communications in Heat and Mass Transfer |
| Volume | 109 |
| Early online date | 31 Oct 2019 |
| Publication status | Published - Dec 2019 |
Abstract
Fluid flow and heat transfer in annuli appear in various technical applications. One of these are actively cooled underground cables, which are a solution for high-voltage transmission grids that face overloads due to a growing capacity of renewable sources. The cooling of these systems depends on precise prediction of heat transfer of a highly eccentric annulus in a way that has not been subject to any known literature or former research. This article presents Nusselt numbers obtained from CFD calculations for turbulent flow (20,000 < Re < 150,000) in highly eccentric annuli (dimensionless eccentricity e up to 0.95). The mesh and turbulence models are validated with well-known correlations from literature, which show very good accordance. Nusselt numbers show a high dependency on the eccentricity. They strongly decrease for e > 0.5 and drop to a third and less for e = 0.95 in comparison to concentric annuli. This has significant impact on the assurance of safe operation in actively cooled cable systems. Results also indicate a change of flow characteristics from laminar to turbulent depending on the eccentricity that should be considered in order to improve heat transfer.
Keywords
- Annulus, Cooled cable, Eccentric, Forced convection, Heat transfer, Nusselt number
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Atomic and Molecular Physics, and Optics
- Chemical Engineering(all)
- General Chemical Engineering
- Physics and Astronomy(all)
- Condensed Matter Physics
Sustainable Development Goals
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In: International Communications in Heat and Mass Transfer, Vol. 109, 104344, 12.2019.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Nusselt numbers from numerical investigations of turbulent flow in highly eccentric horizontal annuli
AU - Zimmermann, Conrad
AU - Lemcke, Felix J.
AU - Kabelac, Stephan
PY - 2019/12
Y1 - 2019/12
N2 - Fluid flow and heat transfer in annuli appear in various technical applications. One of these are actively cooled underground cables, which are a solution for high-voltage transmission grids that face overloads due to a growing capacity of renewable sources. The cooling of these systems depends on precise prediction of heat transfer of a highly eccentric annulus in a way that has not been subject to any known literature or former research. This article presents Nusselt numbers obtained from CFD calculations for turbulent flow (20,000 < Re < 150,000) in highly eccentric annuli (dimensionless eccentricity e up to 0.95). The mesh and turbulence models are validated with well-known correlations from literature, which show very good accordance. Nusselt numbers show a high dependency on the eccentricity. They strongly decrease for e > 0.5 and drop to a third and less for e = 0.95 in comparison to concentric annuli. This has significant impact on the assurance of safe operation in actively cooled cable systems. Results also indicate a change of flow characteristics from laminar to turbulent depending on the eccentricity that should be considered in order to improve heat transfer.
AB - Fluid flow and heat transfer in annuli appear in various technical applications. One of these are actively cooled underground cables, which are a solution for high-voltage transmission grids that face overloads due to a growing capacity of renewable sources. The cooling of these systems depends on precise prediction of heat transfer of a highly eccentric annulus in a way that has not been subject to any known literature or former research. This article presents Nusselt numbers obtained from CFD calculations for turbulent flow (20,000 < Re < 150,000) in highly eccentric annuli (dimensionless eccentricity e up to 0.95). The mesh and turbulence models are validated with well-known correlations from literature, which show very good accordance. Nusselt numbers show a high dependency on the eccentricity. They strongly decrease for e > 0.5 and drop to a third and less for e = 0.95 in comparison to concentric annuli. This has significant impact on the assurance of safe operation in actively cooled cable systems. Results also indicate a change of flow characteristics from laminar to turbulent depending on the eccentricity that should be considered in order to improve heat transfer.
KW - Annulus
KW - Cooled cable
KW - Eccentric
KW - Forced convection
KW - Heat transfer
KW - Nusselt number
UR - http://www.scopus.com/inward/record.url?scp=85074126753&partnerID=8YFLogxK
U2 - 10.1016/j.icheatmasstransfer.2019.104344
DO - 10.1016/j.icheatmasstransfer.2019.104344
M3 - Article
AN - SCOPUS:85074126753
VL - 109
JO - International Communications in Heat and Mass Transfer
JF - International Communications in Heat and Mass Transfer
SN - 0735-1933
M1 - 104344
ER -