Performance investigation on twisted elliptical tube heat exchangers with coupling-vortex square tube layout

Research output: Contribution to journalArticle

Abstract

The twisted elliptical tube heat exchangers with the novel coupling-vortex chessboard tube layout (TETHXs-CV) were simulated with the RNG k-ε model in software Fluent 15.0. The shell-side flow pattern at the tangential points between adjacent tubes in traditional TETHX is countercurrent while that in TETHX-CV is concurrent, which helps enhance heat transfer capability without any extra manufacturing cost. The impacts of the ratio A/B of the major axis to the minor axis and the twist pitch S were also investigated. The results indicate that with the increase of A/B and the decrease of S, the secondary flow behaves more intensely, the Nusselt number Nu and the friction factor f increase, while with the increase of A/B and S, the comprehensive evaluation index Nu∙f−1/3 increases. The Nu, f and Nu∙f−1/3 of all twisted tube schemes are higher than those of the smooth round tube schemes R10.8. Compared with corresponding parallel-vortex schemes, the coupling-vortex schemes possess more uniform temperature fields, and the average Nu, f and Nu∙f−1/3 of the coupling-vortex schemes C12.3S50/C12.3S100 increase by 12.8%/9.9%, 15.2%/10.5% and 7.6%/6.3%, respectively; the smaller S or the closer A/B is to 1, the more advantageous the TETHX-CV.

Details

Authors
Organisations
External organisations
  • Southeast University
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Energy Engineering

Keywords

  • Chessboard square tube layout, Coupling-vortex, Helical pitch, Parallel-vortex, Twisted elliptical tube heat exchangers
Original languageEnglish
Article number119473
JournalInternational Journal of Heat and Mass Transfer
Volume151
Publication statusPublished - 2020
Publication categoryResearch
Peer-reviewedYes