Influence of buoyancy effects on supercritical pressure carbon dioxide convective heat transfer in triply periodic minimal surface (TPMS) channels
File(s)
Accepted version
Author(s)
Wang, Jinghan
Zeng, Min
Markides, Christos N
Wang, Qiuwang
Cheng, Zhilong
Type
Journal Article
Abstract
Triply periodic minimal surface structures have emerged as promising candidates for compact thermal–hydraulic components in supercritical carbon dioxide Brayton cycles. However, under high heat flux or low mass flux scenarios, the drastic density gradients near the pseudo-critical point cause buoyancy forces to become comparable to inertial forces. This transition from forced to mixed convection induces significant flow distortion and thermal stratification, which can cause localized overheating and threaten equipment integrity. Unlike in circular tubes, the coupling mechanism between buoyancy forces and complex TPMS topologies remains unclear. To address this gap, this study employed pore-scale numerical simulations to investigate the flow and heat transfer characteristics of supercritical pressure carbon dioxide in horizontal I-WP and Primitive channels. The results indicate that the I-WP channel eliminates thermal stratification through intense turbulent mixing, while the straight-through pore structure of the Primitive channel results in high-velocity flows with relatively lower TKE under identical conditions, rendering its heat transfer more susceptible to buoyancy effects. Increasing mass flux suppresses buoyancy through enhanced inertia, whereas higher heat flux amplifies it through larger density gradients. Furthermore, the buoyancy parameter (Gr/Re2) is employed to quantitatively evaluate the competition between buoyancy and inertia. In the Primitive channel, this competition is dictated by the coupled effects of thermal property variations and geometric non-uniformity.
Date Issued
2026-09-01
Date Acceptance
2026-05-01
Citation
Energy Conversion and Management, 2026, 363
ISSN
0196-8904
Publisher
Elsevier BV
Journal / Book Title
Energy Conversion and Management
Volume
363
Copyright Statement
Copyright © 2026 Elsevier Ltd. This is the author’s accepted manuscript made available under a CC-BY licence in accordance with Imperial’s Research Publications Open Access policy (www.imperial.ac.uk/oa-policy)
License URL
Publication Status
Published
Article Number
121614
Date Publish Online
2026-05-22