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On the solar receiver thermal enhancement by using the dimple combined with delta winglet vortex generator

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Author

  • Luo Lei
  • Fengbo Wen
  • Lei Wang
  • Bengt Sundén
  • Songtao Wang

Summary, in English

In this study, effects of dimples and their arrangement on the flow structure, heat transfer and friction factor in a solar receiver heated channel with delta-winglet vortex generators (DWVGs) are numerically studied. The dimples are placed either in an inline or a staggered layout. A smooth channel with pure dimples and a smooth channel with pure DWVGs are studied, in which the smooth channel with DWVGs is considered as baseline. The Reynolds number is ranging from 4000 to 40,000. Results of the flow structure, heat plate Nu number, friction factor, temperature and turbulent kinetic energy (TKE) are included. The results show that the adoption of dimples significantly impacts the flow structure by interacting with the vortex which is generated by the DWVGs. A small part of the vortex moves downward and impinges on the inline arranged dimpled surface, which is beneficial for the heat transfer enhancement. However, for the staggered arrangement of dimples, the vortex flow is lifted upward before it impinges on the dimple surface. In this case, the inline arrangement dimples provides the best mixing and the highest heat transfer performance. The heat transfer is augmented by 36.23% while the friction factor is increased by 36.29% compared to the Baseline, respectively. The thermal performance analysis indicates that the use of dimples increases the thermal performance by 28.50%. It is also found that the adoption of inline dimples contributes to the optimal thermal performance and mixing of the cold and hot fluid.

Department/s

Publishing year

2017-01-25

Language

English

Pages

586-598

Publication/Series

Applied Thermal Engineering

Volume

111

Document type

Journal article

Publisher

Elsevier

Topic

  • Energy Engineering

Keywords

  • Delta-winglet vortex generator
  • Dimples
  • Inline and staggered layout
  • Solar receiver
  • Thermal enhancement

Status

Published

ISBN/ISSN/Other

  • ISSN: 1359-4311