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The influence of multi-walled carbon nanotubes on single-phase heat transfer and pressure drop characteristics in the transitional flow regime of smooth tubes
Dissertation (MEng)--University of Pretoria, 2012.
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| Format: | Thesis |
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University of Pretoria
2013
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| _version_ | 1867613469095755776 |
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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 | © 2012 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, 2012. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/25434 |
| institution | University of Pretoria (South Africa) |
| last_indexed | 2026-06-10T12:36:38.421Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2013 |
| publishDateRange | 2013 |
| publishDateSort | 2013 |
| 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:2263/25434 The influence of multi-walled carbon nanotubes on single-phase heat transfer and pressure drop characteristics in the transitional flow regime of smooth tubes Meyer, Josua P. McKrell, T.J. kekegrote@gmail.com Grote, Kersten Multi-walled carbon nanotubes Convective heat transfer Transition Performance evaluation Nanofluids UCTD Dissertation (MEng)--University of Pretoria, 2012. There are in general two different types of studies concerning nanofluids. The first one concerns itself with the study of the effective thermal conductivity and the other with the study of convective heat transfer enhancement. The study on convective heat transfer enhancement generally incorporates the study on the thermal conductivity. Not many papers have been written on the convective heat transfer enhancement and even fewer concerning the study on multi-walled carbon nanotubes in the transitional flow regime. In this paper the thermal conductivity and viscosity was determined experimentally in order to study the convective heat transfer enhancement of the nanofluids. Multi-walled carbon nanotubes suspended in distilled water flowing through a straight, horizontal tube was investigated experimentally for a Reynolds number range of a 1 000 - 8 000, which included the transitional flow regime. The tube was made out of copper and has an internal diameter of 5.16 mm. Results on the thermal conductivity and viscosity indicated that they increase with nanoparticle concentration. Convective heat transfer experiments were conducted at a constant heat flux of 13 kW/m2 with 0.33%, 0.75% and 1.0% volume concentrations of multi-walled carbon nanotubes. The nanotubes had an outside diameter of 10 - 20 nm, an inside diameter of 3 - 5 nm and a length of 10 - 30 μm. Temperature and pressure drop measurements were taken from which the heat transfer coefficients and friction factors were determined as a function of Reynolds number. The thermal conductivities and viscosities of the nanofluids were also determined experimentally so that the Reynolds and Nusselt numbers could be determined accurately. It was found that heat transfer was enhanced when comparing the data on a Nusselt number as a function of Reynolds number graph but comparing the results on a heat transfer coefficient as a function of average velocity graph the opposite effect was observed. Performance evaluation of the nanofluids showed that the increase in viscosity was four times the increase in the thermal conductivity which resulted in an inefficient nanofluid. However, a study on the performance evaluation criterion showed that operating nanofluids in the transition and turbulent flow regime due to the energy budget being better than that of the distilled water. Mechanical and Aeronautical Engineering unrestricted 2013-09-06T21:19:16Z 2013-06-12 2013-09-06T21:19:16Z 2013-04-15 2012 2013-06-10 Dissertation Grote, K 2012, The influence of multi-walled carbon nanotubes on single-phase heat transfer and pressure drop characteristics in the transitional flow regime of smooth tubes, MEng dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/25434 > E13/4/728/gm http://hdl.handle.net/2263/25434 http://upetd.up.ac.za/thesis/available/etd-06102013-163652/ © 2012 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 | Multi-walled carbon nanotubes Convective heat transfer Transition Performance evaluation Nanofluids UCTD The influence of multi-walled carbon nanotubes on single-phase heat transfer and pressure drop characteristics in the transitional flow regime of smooth tubes |
| title | The influence of multi-walled carbon nanotubes on single-phase heat transfer and pressure drop characteristics in the transitional flow regime of smooth tubes |
| title_full | The influence of multi-walled carbon nanotubes on single-phase heat transfer and pressure drop characteristics in the transitional flow regime of smooth tubes |
| title_fullStr | The influence of multi-walled carbon nanotubes on single-phase heat transfer and pressure drop characteristics in the transitional flow regime of smooth tubes |
| title_full_unstemmed | The influence of multi-walled carbon nanotubes on single-phase heat transfer and pressure drop characteristics in the transitional flow regime of smooth tubes |
| title_short | The influence of multi-walled carbon nanotubes on single-phase heat transfer and pressure drop characteristics in the transitional flow regime of smooth tubes |
| title_sort | influence of multi walled carbon nanotubes on single phase heat transfer and pressure drop characteristics in the transitional flow regime of smooth tubes |
| topic | Multi-walled carbon nanotubes Convective heat transfer Transition Performance evaluation Nanofluids UCTD |
| url | http://hdl.handle.net/2263/25434 http://upetd.up.ac.za/thesis/available/etd-06102013-163652/ |