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Surface temperature uniformity for single-phase developing laminar flow through horizontal tubes submerged in boiling water

Dissertation (MSc (Applied Science Mechanics)--University of Pretoria, 2022.

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Other Authors: Evets, Marilize
Format: Thesis
Language:English
Published: University of Pretoria 2023
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access_status_str Open Access
author2 Evets, Marilize
author_browse Evets, Marilize
author_facet Evets, Marilize
collection Thesis
dc_rights_str_mv © 2022 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.
description Dissertation (MSc (Applied Science Mechanics)--University of Pretoria, 2022.
format Thesis
id oai:repository.up.ac.za:2263/89692
institution University of Pretoria (South Africa)
language English
last_indexed 2026-06-10T12:36:49.486Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository
publishDate 2023
publishDateRange 2023
publishDateSort 2023
publisher University of Pretoria
publisherStr University of Pretoria
record_format dspace
source_str UPSpace — University of Pretoria Institutional Repository
spelling oai:repository.up.ac.za:2263/89692 Surface temperature uniformity for single-phase developing laminar flow through horizontal tubes submerged in boiling water Evets, Marilize rudavirogoodwill@gmail.com Munzara, Rudaviro UCTD Uniform surface temperature Laminar Nucleate boiling Convection heat transfer Thermally developing flow Engineering, built environment and information technology theses SDG-07 SDG-07: Affordable and clean energy Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Dissertation (MSc (Applied Science Mechanics)--University of Pretoria, 2022. An experimental study was done to investigate the heat transfer characteristics of simultaneously hydrodynamically and thermally developing laminar flow of water through a horizontal tube, which was submerged in boiling water to keep its surface temperature uniform. A water bath with two compartments was used to house the water at saturation whose boiling was brought about by heater elements that covered the base area of the water bath. The inside and outside diameters of the test section were 11.2 mm and 12.5 mm, respectively, and the heated length was 1 m. Experiments were conducted between Reynolds numbers of 500 and 3 000 considering different heat input levels and inlet temperatures that varied between 20 °C and 80 °C. Although nucleate pool boiling was expected to provide a uniform surface temperature, thermocouple measurements on the test section showed that the wetted surface temperatures on the inside of the test section were not uniform when the flow was still thermally developing. The surface temperatures increased and approached a constant along the length of the test section. The effects of varying the Reynolds number, the tube inlet temperatures and the heat input into the system on the surface temperatures’ uniformity were investigated. In none of the tests taken were the surface temperatures sufficiently uniform although the degrees of surface temperature uniformity changed with the variation of these factors. For the first time, it has been established that the assumption of a uniform surface temperature during phase-change conditions is not valid for developing flow. From the several analyses done, it was concluded that the high heat transfer coefficients associated with developing flow significantly affected the surface temperatures’ uniformity as these were found to be dominant in the entrance region. Therefore, the general assumption of a uniform surface temperature boundary condition during phase-change conditions would only be valid for fully developed flow. German Academic Exchange Service (DAAD) Clean Energy Research Group- UP mi2025 Mechanical and Aeronautical Engineering MSc (Applied Science Mechanics) Unrestricted SDG-07: Affordable and clean energy SDG-09: Industry, innovation and infrastructure 2023-02-20T05:51:20Z 2023-02-20T05:51:20Z 2023-04 2022 Dissertation * A2023 https://repository.up.ac.za/handle/2263/89692 10.25403/UPresearchdata.22116308 en © 2022 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria
spellingShingle UCTD
Uniform surface temperature
Laminar
Nucleate boiling
Convection heat transfer
Thermally developing flow
Engineering, built environment and information technology theses SDG-07
SDG-07: Affordable and clean energy
Engineering, built environment and information technology theses SDG-09
SDG-09: Industry, innovation and infrastructure
Surface temperature uniformity for single-phase developing laminar flow through horizontal tubes submerged in boiling water
title Surface temperature uniformity for single-phase developing laminar flow through horizontal tubes submerged in boiling water
title_full Surface temperature uniformity for single-phase developing laminar flow through horizontal tubes submerged in boiling water
title_fullStr Surface temperature uniformity for single-phase developing laminar flow through horizontal tubes submerged in boiling water
title_full_unstemmed Surface temperature uniformity for single-phase developing laminar flow through horizontal tubes submerged in boiling water
title_short Surface temperature uniformity for single-phase developing laminar flow through horizontal tubes submerged in boiling water
title_sort surface temperature uniformity for single phase developing laminar flow through horizontal tubes submerged in boiling water
topic UCTD
Uniform surface temperature
Laminar
Nucleate boiling
Convection heat transfer
Thermally developing flow
Engineering, built environment and information technology theses SDG-07
SDG-07: Affordable and clean energy
Engineering, built environment and information technology theses SDG-09
SDG-09: Industry, innovation and infrastructure
url https://repository.up.ac.za/handle/2263/89692