Title page for ETD etd-07112011-112410


Document Type Master's Dissertation
Author Ogunronbi, Oluseun Ifeanyi
URN etd-07112011-112410
Document Title Maximum heat transfer rate density from a rotating multiscale array of cylinders
Degree MEng
Department Mechanical and Aeronautical Engineering
Supervisor
Advisor Name Title
Prof J P Meyer Co-Supervisor
Dr T Bello-Ochende Supervisor
Keywords
  • counter-rotating
  • dimensionless
  • heattransfer rate density
  • leading edge
  • multiscale
  • pressure drop number
  • co-rotating
  • centreline
Date 2011-04-06
Availability unrestricted
Abstract
This work investigated a numerical approach to the search of a maximum heat transfer rate density (the overall heat transfer dissipated per unit of volume) from a two-dimensional laminar multiscale array of cylinders in cross-flow under an applied fixed pressure drop and subject to the constraint of fixed volume. It was furthermore assumed that the flow field was steady state and incompressible. The configuration had two degrees of freedom in the stationary state, that is, the spacing between the cylinders and the diameter of the smaller cylinders. The angular velocity of the cylinders was in the range 0 ≤ ϖ, ≤ 0.1. Two cylinders of different diameters were used, in the first case, the cylinders were aligned along a plane which lay on their centrelines. In the second case, the cylinder leading edge was aligned along the plane that received the incoming fluid at the same time. The diameter of the smaller cylinder was fixed at the optimal diameter obtained when the cylinders were stationary. Tests were conducted for co-rotating and counterrotating cylinders. The results were also compared with results obtained in the open literature and the trend was found to be the same. Results showed that the heat transfer from a rotating array of cylinders was enhanced in certain cases and this was observed for both directions of rotation from an array which was aligned on the centreline. For rotating cylinders with the same leading edge, there is heat transfer suppression and hence the effect of rotation on the maximum heat transfer rate density is insignificant. This research is important in further understanding of heat transfer from rotating cylinders, which can be applied to applications ranging from contact cylinder dryers in the chemical processes industry and rotating cylinder electrodes to devices used for roller hearth furnaces.

2010, 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.

Please cite as follows:

Ogunronbi, OI 2010, Maximum heat transfer rate density from a rotating multiscale array of cylinders, MEng dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-07112011-112410 / >

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