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Study of flow and heat transfer features of nanofluids using multiphase models : eulerian multiphase and discrete Lagrangian approaches
Thesis (PhD)--University of Pretoria, 2016.
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University of Pretoria
2017
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| _version_ | 1867613463984996352 |
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| access_status_str | Open Access |
| author2 | Sharifpur, Mohsen |
| author_browse | Sharifpur, Mohsen |
| author_facet | Sharifpur, Mohsen |
| 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 | Thesis (PhD)--University of Pretoria, 2016. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/61309 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:36:33.567Z |
| 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:2263/61309 Study of flow and heat transfer features of nanofluids using multiphase models : eulerian multiphase and discrete Lagrangian approaches Sharifpur, Mohsen mostafa.mahdavi@up.ac.za Meyer, Josua P. Mahdavi, Mostafa UCTD Nanofluid Eulerian-Eulerian Eulerian-Lagrangian User-defined Function 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-12 SDG-12: Responsible consumption and production Thesis (PhD)--University of Pretoria, 2016. Choosing correct boundary conditions, flow field characteristics and employing right thermal fluid properties can affect the simulation of convection heat transfer using nanofluids. Nanofluids have shown higher heat transfer performance in comparison with conventional heat transfer fluids. The suspension of the nanoparticles in nanofluids creates a larger interaction surface to the volume ratio. Therefore, they can be distributed uniformly to bring about the most effective enhancement of heat transfer without causing a considerable pressure drop. These advantages introduce nanofluids as a desirable heat transfer fluid in the cooling and heating industries. The thermal effects of nanofluids in both forced and free convection flows have interested researchers to a great extent in the last decade. Investigating the interaction mechanisms happening between nanoparticles and base fluid is the main goal of the study. These mechanisms can be explained via different approaches through some theoretical and numerical methods. Two common approaches regarding particle-fluid interactions are Eulerian-Eulerian and Eulerian-Lagrangian. The dominant conceptions in each of them are slip velocity and interaction forces respectively. The mixture multiphase model as part of the Eulerian-Eulerian approach deals with slip mechanisms and somehow mass diffusion from the nanoparticle phase to the fluid phase. The slip velocity can be induced by a pressure gradient, buoyancy, virtual mass, attraction and repulsion between particles. Some of the diffusion processes can be caused by the gradient of temperature and concentration. The discrete phase model (DPM) is a part of the Eulerian-Lagrangian approach. The interactions between solid and liquid phase were presented as forces such as drag, pressure gradient force, virtual mass force, gravity, electrostatic forces, thermophoretic and Brownian forces. The energy transfer from particle to continuous phase can be introduced through both convective and conduction terms on the surface of the particles. A study of both approaches was conducted in the case of laminar and turbulent forced convections as well as cavity flow natural convection. The cases included horizontal and vertical pipes and a rectangular cavity. An experimental study was conducted for cavity flow to be compared with the simulation results. The results of the forced convections were evaluated with data from literature. Alumina and zinc oxide nanoparticles with different sizes were used in cavity experiments and the same for simulations. All the equations, slip mechanisms and forces were implemented in ANSYS-Fluent through some user-defined functions. The comparison showed good agreement between experiments and numerical results. Nusselt number and pressure drops were the heat transfer and flow features of nanofluid and were found in the ranges of the accuracy of experimental measurements. The findings of the two approaches were somehow different, especially regarding the concentration distribution. The mixture model provided more uniform distribution in the domain than the DPM. Due to the Lagrangian frame of the DPM, the simulation time of this model was much longer. The method proposed in this research could also be a useful tool for other areas of particulate systems. mi2025 Mechanical and Aeronautical Engineering PhD Unrestricted SDG-07: Affordable and clean energy SDG-09: Industry, innovation and infrastructure SDG-12: Responsible consumption and production 2017-07-13T13:28:52Z 2017-07-13T13:28:52Z 2017-04-26 2016 Thesis Mahdavi, M 2016, Study of flow and heat transfer features of nanofluids using multiphase models : eulerian multiphase and discrete Lagrangian approaches, PhD Thesis, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/61309> A2017 http://hdl.handle.net/2263/61309 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 Nanofluid Eulerian-Eulerian Eulerian-Lagrangian User-defined Function 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-12 SDG-12: Responsible consumption and production Study of flow and heat transfer features of nanofluids using multiphase models : eulerian multiphase and discrete Lagrangian approaches |
| title | Study of flow and heat transfer features of nanofluids using multiphase models : eulerian multiphase and discrete Lagrangian approaches |
| title_full | Study of flow and heat transfer features of nanofluids using multiphase models : eulerian multiphase and discrete Lagrangian approaches |
| title_fullStr | Study of flow and heat transfer features of nanofluids using multiphase models : eulerian multiphase and discrete Lagrangian approaches |
| title_full_unstemmed | Study of flow and heat transfer features of nanofluids using multiphase models : eulerian multiphase and discrete Lagrangian approaches |
| title_short | Study of flow and heat transfer features of nanofluids using multiphase models : eulerian multiphase and discrete Lagrangian approaches |
| title_sort | study of flow and heat transfer features of nanofluids using multiphase models eulerian multiphase and discrete lagrangian approaches |
| topic | UCTD Nanofluid Eulerian-Eulerian Eulerian-Lagrangian User-defined Function 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-12 SDG-12: Responsible consumption and production |
| url | http://hdl.handle.net/2263/61309 |