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Thermal enhancement by using grooves and ribs combined with delta-winglet vortex generator in a solar receiver heat exchanger

Lei, Luo LU ; Wen, Fengbo; Wang, Lei LU ; Sundén, Bengt LU and Wang, Songtao (2016) In Applied Energy 183. p.1317-1332
Abstract

A good heat transfer performance with moderate pressure drop penalty, as well as a high mixing effect contributes to the increase of a solar receiver thermal efficiency. In this study, delta-winglet vortex generators (DWVGs), and the combination of DWVGs and obstacles are numerically studied to reveal the effects on a solar receiver heat exchanger and the heat transfer, friction factor and mixing. The DWVGs are placed on the heated plate. Four different obstacles, i.e., perturbation triangular ribs, perturbation semi-cylinder ribs, triangular grooves and semi-cylinder grooves, are studied. The Reynolds number is ranging from 4000 to 40,000. Results of the flow field, heated plate Nu number, friction factor, temperature and turbulent... (More)

A good heat transfer performance with moderate pressure drop penalty, as well as a high mixing effect contributes to the increase of a solar receiver thermal efficiency. In this study, delta-winglet vortex generators (DWVGs), and the combination of DWVGs and obstacles are numerically studied to reveal the effects on a solar receiver heat exchanger and the heat transfer, friction factor and mixing. The DWVGs are placed on the heated plate. Four different obstacles, i.e., perturbation triangular ribs, perturbation semi-cylinder ribs, triangular grooves and semi-cylinder grooves, are studied. The Reynolds number is ranging from 4000 to 40,000. Results of the flow field, heated plate Nu number, friction factor, temperature and turbulent kinetic energy (TKE) are included. A smooth channel with DWVGs is considered as the baseline. The results showed that the adoption of DWVGs induces pressure gradients on more than one direction and thus vortices are generated. The flow velocity is increased as the flow approaches the DWVGs. The perturbation semi-cylinder ribs provide the highest heat transfer augmentation as the vortex is disturbed by the smooth cylinder surface. The thermal performance indicates that the semi-cylinder grooves together with DWVGs provide the highest performance and also an augmented mixing effect is found.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Delta-winglet vortex generator, Groove, Rib, Solar receiver, Thermal enhancement
in
Applied Energy
volume
183
pages
16 pages
publisher
Elsevier
external identifiers
  • scopus:84991666099
  • wos:000395726400035
ISSN
0306-2619
DOI
10.1016/j.apenergy.2016.09.077
language
English
LU publication?
yes
id
c66f5c78-b860-4ef9-b036-5cc1e73a1a48
date added to LUP
2016-11-04 09:31:02
date last changed
2017-09-18 11:29:16
@article{c66f5c78-b860-4ef9-b036-5cc1e73a1a48,
  abstract     = {<p>A good heat transfer performance with moderate pressure drop penalty, as well as a high mixing effect contributes to the increase of a solar receiver thermal efficiency. In this study, delta-winglet vortex generators (DWVGs), and the combination of DWVGs and obstacles are numerically studied to reveal the effects on a solar receiver heat exchanger and the heat transfer, friction factor and mixing. The DWVGs are placed on the heated plate. Four different obstacles, i.e., perturbation triangular ribs, perturbation semi-cylinder ribs, triangular grooves and semi-cylinder grooves, are studied. The Reynolds number is ranging from 4000 to 40,000. Results of the flow field, heated plate Nu number, friction factor, temperature and turbulent kinetic energy (TKE) are included. A smooth channel with DWVGs is considered as the baseline. The results showed that the adoption of DWVGs induces pressure gradients on more than one direction and thus vortices are generated. The flow velocity is increased as the flow approaches the DWVGs. The perturbation semi-cylinder ribs provide the highest heat transfer augmentation as the vortex is disturbed by the smooth cylinder surface. The thermal performance indicates that the semi-cylinder grooves together with DWVGs provide the highest performance and also an augmented mixing effect is found.</p>},
  author       = {Lei, Luo and Wen, Fengbo and Wang, Lei and Sundén, Bengt and Wang, Songtao},
  issn         = {0306-2619},
  keyword      = {Delta-winglet vortex generator,Groove,Rib,Solar receiver,Thermal enhancement},
  language     = {eng},
  month        = {12},
  pages        = {1317--1332},
  publisher    = {Elsevier},
  series       = {Applied Energy},
  title        = {Thermal enhancement by using grooves and ribs combined with delta-winglet vortex generator in a solar receiver heat exchanger},
  url          = {http://dx.doi.org/10.1016/j.apenergy.2016.09.077},
  volume       = {183},
  year         = {2016},
}