dc.contributor.author |
Everts, Marilize
|
|
dc.contributor.author |
Mahdavi, Mostafa
|
|
dc.contributor.author |
Sharifpur, Mohsen
|
|
dc.contributor.author |
Meyer, Josua P.
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|
dc.date.accessioned |
2023-11-29T09:34:59Z |
|
dc.date.issued |
2023-05 |
|
dc.description |
DATA AVAILABILITY : Data will be made available on request. |
en_US |
dc.description.abstract |
The thermal and hydrodynamic features of developing mixed convective laminar flow in a long horizontal tube were numerically and experimentally investigated. The tube was heated at different constant heat fluxes and had an inner diameter of 11.52 mm and a total length of 9.5 m. Numerical simulations were conducted using ANSYS-Fluent 19.3 with a highly structured mesh and accurate temperature-dependant thermophysical properties for water. The studied parameters consisted of the wall temperatures, Nusselt numbers, vorticity, velocity and temperature gradients, hydrodynamic and thermal boundary layer development, secondary flow, as well as significant momentum terms. By analysing the vorticity characteristics, it was found that our conventional understanding of the merging boundary layer in internal tube flows had to be modified. Subsequently, methods were proposed to determine the development of the hydrodynamic and thermal boundary layers, as well as the momentum terms. The experimental and numerical results indicated that the local mixed convective Nusselt numbers decreased near the tube inlet but then increased along the tube length as secondary flow increased significantly. Furthermore, an increase in secondary flow led to a decreased thermal entrance length but increased hydrodynamic entrance length. By analysing the simultaneous development of the hydrodynamic and thermal boundary layers, it was revealed that the entrance region of a mixed convective laminar flow could be divided into six regions: (1) hydrodynamic inlet region, (2) buoyancy development region, (3) buoyancy dominating region, (4) buoyancy settling region, (5) hydrodynamically stabilising region, and (6) fully developed region. |
en_US |
dc.description.department |
Mechanical and Aeronautical Engineering |
en_US |
dc.description.embargo |
2024-01-25 |
|
dc.description.librarian |
hj2023 |
en_US |
dc.description.sdg |
None |
en_US |
dc.description.sponsorship |
The National Research Foundation, Department of Science and Innovation (DSI), and the University of Pretoria. |
en_US |
dc.description.uri |
https://www.elsevier.com/locate/ijts |
en_US |
dc.identifier.citation |
Everts, M., Mahdavi, M., Sharifpur, M. & Meyer, J.P. 2023, 'Simultaneous development of the hydrodynamic and thermal boundary layers of mixed convective laminar flow through a horizontal tube with a constant heat flux', International Journal of Thermal Sciences, vol. 187, art. 108178, pp. 1-21, doi : 10.1016/j.ijthermalsci.2023.108178. |
en_US |
dc.identifier.issn |
1290-0729 (print) |
|
dc.identifier.issn |
1778-4166 (online) |
|
dc.identifier.other |
10.1016/j.ijthermalsci.2023.108178 |
|
dc.identifier.uri |
http://hdl.handle.net/2263/93535 |
|
dc.language.iso |
en |
en_US |
dc.publisher |
Elsevier |
en_US |
dc.rights |
© 2023 Elsevier Masson SAS. All rights reserved. Notice : this is the author’s version of a work that was accepted for publication inInternational Journal of Thermal Sciences . Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. A definitive version was subsequently published in International Journal of Thermal Sciences, vol. 187, art. 108178, pp. 1-21, doi : 10.1016/j.ijthermalsci.2023.108178. |
en_US |
dc.subject |
Mixed convection |
en_US |
dc.subject |
Hydrodynamic boundary layer |
en_US |
dc.subject |
Thermal boundary layer |
en_US |
dc.subject |
Boundary layer thickness |
en_US |
dc.subject |
Simultaneous developing |
en_US |
dc.subject |
Computational fluid dynamics (CFD) |
en_US |
dc.title |
Simultaneous development of the hydrodynamic and thermal boundary layers of mixed convective laminar flow through a horizontal tube with a constant heat flux |
en_US |
dc.type |
Postprint Article |
en_US |