Al-Asadi, MT, Alkasmoul, FS and Wilson, MCT orcid.org/0000-0002-1058-2003 (2018) Benefits of spanwise gaps in cylindrical vortex generators for conjugate heat transfer enhancement in micro-channels. Applied Thermal Engineering, 130. pp. 571-586. ISSN 1359-4311
Abstract
Cylindrical vortex generators placed transversely over the span of a micro-channel can enhance heat transfer performance, but adding full-span vortex generators incurs a substantial pressure drop penalty. This paper examines the benefits of introducing various gaps along the length of the vortex generators, both for reducing pressure drop and improving the thermal conductance of the system. Three particular configurations are considered with varied dimensions: symmetrical gaps at each end of the vortex generator, i.e. adjacent to the channel side walls; a single central gap; and a combination of a central and end gaps. The performance is investigated numerically via 3D finite element analysis for Reynolds number in the range 300–2300 and under conditions of a uniform heat flux input relevant to microelectronics cooling. Results demonstrate that having end gaps alone substantially improves heat transfer while reducing the pressure drop. As well as generating longitudinal vortices which draw heat from the adjacent channel side walls, hot fluid passing through the gaps is swept directly upwards and inwards into the bulk flow, where it remains as it flows to the outlet. A thermal-hydraulic performance evaluation index is improved from 0.7 for full-span vortex generators to 1.0 with end gaps present. The central and central-plus-end gap geometries are less effective overall, but do offer localised improvements in heat transfer.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Copyright, Publisher and Additional Information: | Crown Copyright © 2017 Published by Elsevier Ltd. This is an author produced version of a paper published in Applied Thermal Engineering. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Longitudinal and transverse vortices; Micro-channel; Thermal hydraulic performance; Micro-scale cooling system; Heat transfer enhancement; Gap effect |
Dates: |
|
Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Mechanical Engineering (Leeds) > Institute of Engineering Thermofluids, Surfaces & Interfaces (iETSI) (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 08 Nov 2017 09:13 |
Last Modified: | 31 Oct 2018 01:38 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.applthermaleng.2017.10.157 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:123640 |