Performance investigation on twisted elliptical tube heat exchangers with coupling-vortex square tube layout
Research output: Contribution to journal › Article
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.
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Research areas and keywords | Subject classification (UKÄ) – MANDATORY
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Original language | English |
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Article number | 119473 |
Journal | International Journal of Heat and Mass Transfer |
Volume | 151 |
Publication status | Published - 2020 |
Publication category | Research |
Peer-reviewed | Yes |