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Qualitative analysis of flow patterns : two-phase flow condensation at low mass fluxes and different inclination angles
Dissertation (MSc)--University of Pretoria, 2016.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2017
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| _version_ | 1867613522515460096 |
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| access_status_str | Open Access |
| author2 | Meyer, Josua P. |
| author_browse | Meyer, Josua P. |
| author_facet | Meyer, Josua P. |
| collection | Thesis |
| dc_rights_str_mv | © 2017 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)--University of Pretoria, 2016. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/61303 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:37:29.335Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2017 |
| publishDateRange | 2017 |
| publishDateSort | 2017 |
| 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:2263/61303 Qualitative analysis of flow patterns : two-phase flow condensation at low mass fluxes and different inclination angles Meyer, Josua P. u13294980@tuks.co.za Kombo, Rainah UCTD Two-phase flow Heat transfer coefficient Flow pattern Low mass flux Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production Dissertation (MSc)--University of Pretoria, 2016. A great deal of work has been conducted on in-tube condensation in horizontal and vertical smooth tubes. The available literature points to mechanisms governing two-phase condensation heat transfer coefficients and pressure drops, which are directly linked to the local flow pattern for both horizontal and inclined configurations. However, the work has been limited to flow pattern observations, heat transfer, pressure drops and void fractions for both horizontal and inclined tubes at high mass fluxes. No work has been conducted on the analysis of the observed flow patterns and the effect of temperature difference between the average wall temperature and average saturation temperature for different inclination angles at mass fluxes of 100 kg/m2.s and below. The purpose of this study is to carry out a qualitative analysis of flow patterns, and show the effect of temperature difference on the heat transfer coefficient for inclination angles from +90° (upward flow) to -90° (downward flow) at mass fluxes below 100 kg/m2.s. An experimental set-up provided the measurements for the two-phase condensation of R-143a in a smooth tube with an inside diameter of 8.38 mm and a length of 1.5 m. The mass fluxes were 25 kg/m2.s to 100 kg/m2.s, the saturation temperature was 40 °C and the mean qualities were 0.1 to 0.9. A high-speed camera was used to visually analyse and determine the flow patterns for both the inlet and the outlet of the test section. Through the results, eight flow patterns were observed: stratified-wavy, stratified, wavy, wavy-churn, intermittent, churn, annular and wavy-annular. The maximum heat transfer was observed for downward flow between inclination angles of -15° and -30°. The Thome-Hajal flow pattern map correctly predicted horizontal flow patterns, but failed to predict most of the inclined flow patterns. Various flow pattern transitions were identified and proposed for all the investigated inclination angles in this study. Finally, the heat transfer coefficient was found to be dependent on quality, mass flux, temperature difference and inclination angle. mi2025 Mechanical and Aeronautical Engineering MSc Unrestricted SDG-09: Industry, innovation and infrastructure SDG-12: Responsible consumption and production 2017-07-13T13:28:50Z 2017-07-13T13:28:50Z 2017-04-26 2016 Dissertation Kombo, R 2016, Qualitative analysis of flow patterns : two-phase flow condensation at low mass fluxes and different inclination angles, MSc Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/61303> A2017 http://hdl.handle.net/2263/61303 en © 2017 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 Two-phase flow Heat transfer coefficient Flow pattern Low mass flux Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production Qualitative analysis of flow patterns : two-phase flow condensation at low mass fluxes and different inclination angles |
| title | Qualitative analysis of flow patterns : two-phase flow condensation at low mass fluxes and different inclination angles |
| title_full | Qualitative analysis of flow patterns : two-phase flow condensation at low mass fluxes and different inclination angles |
| title_fullStr | Qualitative analysis of flow patterns : two-phase flow condensation at low mass fluxes and different inclination angles |
| title_full_unstemmed | Qualitative analysis of flow patterns : two-phase flow condensation at low mass fluxes and different inclination angles |
| title_short | Qualitative analysis of flow patterns : two-phase flow condensation at low mass fluxes and different inclination angles |
| title_sort | qualitative analysis of flow patterns two phase flow condensation at low mass fluxes and different inclination angles |
| topic | UCTD Two-phase flow Heat transfer coefficient Flow pattern Low mass flux Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production |
| url | http://hdl.handle.net/2263/61303 |