A designed wall roughness approach to improve turbulent heat transfer to supercritical CO2 flowing in horizontal tubes

Jianyong Wang*, Jun Yang, Jishuang Gong, Chunrong Zhao, Kamel Hooman

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Supercritical flow through a horizontal pipe leads to a non-uniform peripheral wall temperature distribution even when the wall heat flux is kept constant and uniform. This is attributed to lower heat transfer coefficient at the top section where the denser fluid tends to sink. Hence, to obtain a uniform wall temperature, a designed wall roughness is devised. Uniform sand-grain roughness is employed to only partly cover the top half of the pipe wall. Numerical simulations were conducted using the SST k−ω turbulence model. The simulation results indicate that our proposed design can lead to a more uniform heat transfer distribution over the wall periphery compared with the smooth pipe. An extreme case was also considered where the inner wall was completely covered with roughness elements. While heat transfer augmentation was observed for this case, the excess pressure drop was prohibitively higher compared with a pipe with designed wall roughness.

Original languageEnglish
Article number105738
Number of pages15
JournalJournal of Supercritical Fluids
Volume190
DOIs
Publication statusPublished - 2022

Bibliographical note

Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care
Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Keywords

  • Horizontal pipe
  • Partly
  • Sand-grain roughness
  • Supercritical flow
  • Uniform heat transfer

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