Li, W., Yu, Z. , Wang, Y. and Li, Y. (2022) Heat transfer enhancement of twisted tape inserts in supercritical carbon dioxide flow conditions based on CFD and vortex kinematics. Thermal Science and Engineering Progress, 31, 101285. (doi: 10.1016/j.tsep.2022.101285)
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Abstract
Twisted tape inserts (TTI) are often employed to enhance heat transfer in tubes but their enhancement for supercritical carbon dioxide (SCO2) is unknown, and the thermal performance of TTIs is never studied by vortex kinematics. The TTIs with three twist ratios (TR) were designed for an experimental SCO2 water-cooled counter-flow tube-in-tube heat exchanger, and the convective heat transfer of SCO2 in the exchangers with the TTIs was simulated with ANSYS CFX based on the three-dimensional, Reynolds-averaged Navier-Stokes equations and shear stress transport turbulence model. Effects of TR, mass flux, inlet pressure and wall heat flux on the performance were clarified. The optimal TRs were sought by using the performance evaluation criterion curve and criterion of friction factor ratio ≤5. The thermal performance was characterised by using cross-sectional average absolute helicity. The friction factor ratio, Nusselt number ratio and performance evaluation criterion vary in the ranges of 3.63-7.29, 3.43-5.75 and 1.90-2.94 at the pseudocritical point, inlet pressure of 8MPa, mass flux of 200kg/m2s and wall heat flux of 12kW/m2 as TR=2.17, 3.78, 5.39. The best heat transfer enhancement caused by TTIs appears at the point with 2-3 times better than that in water or air flow. The enhancement reduces dramatically on the left- and right-hand sides of the point. The increased mass flux and inlet pressure can reduce but a large wall flux can raise the enhancement on both sides of the point. The optimal TR depends on SCO2 operational conditions and TR=3.78 is the optimal TR for most cases herein.
| Item Type: | Articles |
|---|---|
| Status: | Published |
| Refereed: | Yes |
| Glasgow Author(s) Enlighten ID: | Li, Dr Wenguang and Yu, Professor Zhibin |
| Authors: | Li, W., Yu, Z., Wang, Y., and Li, Y. |
| College/School: | College of Science and Engineering > School of Engineering > Systems Power and Energy |
| Journal Name: | Thermal Science and Engineering Progress |
| Publisher: | Elsevier |
| ISSN: | 2451-9049 |
| ISSN (Online): | 2451-9049 |
| Published Online: | 31 March 2022 |
| Copyright Holders: | Copyright © 2022 The Authors |
| First Published: | First published in Thermal Science and Engineering Progress 31: 101285 |
| Publisher Policy: | Reproduced under a Creative Commons License |
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