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Experimental investigation of microchannel flow boiling heat transfer with non-uniform circumferential heat flux at various gravitational orientations
Dissertation (MEng)--University of Pretoria, 2020.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2021
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| _version_ | 1867613524150190080 |
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| access_status_str | Open Access |
| author2 | Dirker, Jaco |
| author_browse | Dirker, Jaco |
| author_facet | Dirker, Jaco |
| collection | Thesis |
| dc_rights_str_mv | © 2019 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 (MEng)--University of Pretoria, 2020. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/78356 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:37:30.755Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| 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:2263/78356 Experimental investigation of microchannel flow boiling heat transfer with non-uniform circumferential heat flux at various gravitational orientations Dirker, Jaco u13047541@tuks.co.za Meyer, Josua P. Sefiane, Khellil Vermaak, Marius UCTD Microchannel flow Boiling heat transfer Non-uniform circumferential Heat flux Gravitational orientations 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 Engineering, built environment and information technology theses SDG-13 SDG-13: Climate action Dissertation (MEng)--University of Pretoria, 2020. Flow boiling of Perfluorohexane (FC-72) in rectangular microchannels with one-sided uniform heating was studied experimentally at different rotations (θ). Various rotational orientations were investigated ranging from θ = 0° (bottom-heating) to 90° (side-heating) in increments of 30° as well as 180° (top-heating). The channels had a relatively high aspect ratio of 10 (5 mm x 0.5 mm), a hydraulic diameter of 909 μm and a heated length of approximately 78 mm. Mass fluxes of 10 kg/m2s, 20 kg/m2s and 40 kg/m2s were considered at several heat flux values at a saturation temperature of 56°C. For these conditions, in-channel flow visualisations and heated surface temperature distributions were recorded; fluid temperature and pressure readings were taken, and heat transfer coefficients were determined from subcooled conditions, through the onset of nucleate boiling, to near dryout conditions within the channel. A channel at a rotation of θ = 0° produced the optimal results. θ = 0° had the highest heat transfer coefficient at all mass flux and heat flux combinations tested and had the lowest cross-sectional temperature variation of all rotations, minimizing the probability of warping electronic components. θ = 0° was nucleate boiling dominated resulting in an improved heat transfer performance with an increase in heat flux. θ = 180° experienced heat transfer coefficients that were greater than θ = 30°, 60° and 90° at various qualities up to χ = 0.3 where the vapour slug became confined the heat transfer coefficient decreased rapidly. θ = 90° had the lowest heat transfer coefficients at most mass flux and heat flux test cases. θ = 0° had the highest pressure drop while θ = 180° had the lowest pressure drop. This project received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No. 778104. mi2025 Mechanical and Aeronautical Engineering MEng Unrestricted SDG-07: Affordable and clean energy SDG-09: Industry, innovation and infrastructure SDG-13: Climate action 2021-02-10T06:40:46Z 2021-02-10T06:40:46Z 2021 2020 Dissertation * http://hdl.handle.net/2263/78356 en © 2019 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 Microchannel flow Boiling heat transfer Non-uniform circumferential Heat flux Gravitational orientations 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 Engineering, built environment and information technology theses SDG-13 SDG-13: Climate action Experimental investigation of microchannel flow boiling heat transfer with non-uniform circumferential heat flux at various gravitational orientations |
| title | Experimental investigation of microchannel flow boiling heat transfer with non-uniform circumferential heat flux at various gravitational orientations |
| title_full | Experimental investigation of microchannel flow boiling heat transfer with non-uniform circumferential heat flux at various gravitational orientations |
| title_fullStr | Experimental investigation of microchannel flow boiling heat transfer with non-uniform circumferential heat flux at various gravitational orientations |
| title_full_unstemmed | Experimental investigation of microchannel flow boiling heat transfer with non-uniform circumferential heat flux at various gravitational orientations |
| title_short | Experimental investigation of microchannel flow boiling heat transfer with non-uniform circumferential heat flux at various gravitational orientations |
| title_sort | experimental investigation of microchannel flow boiling heat transfer with non uniform circumferential heat flux at various gravitational orientations |
| topic | UCTD Microchannel flow Boiling heat transfer Non-uniform circumferential Heat flux Gravitational orientations 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 Engineering, built environment and information technology theses SDG-13 SDG-13: Climate action |
| url | http://hdl.handle.net/2263/78356 |