Heat transfer characteristics of lead-bismuth eutectic and CO₂-based mixtures in straight-channel printed circuit heat exchangers
File(s)
Author(s)
Type
Journal Article
Abstract
Lead-cooled fast reactors coupled with supercritical CO2 Brayton cycles represent a highly promising energy conversion technology for next generation nuclear power system. The overall thermal performance of these systems can be further enhanced by introducing CO2-based mixtures, however, investigations on the heat transfer and flow characteristics of lead-bismuth eutectic (LBE) and CO2-based mixtures in the intermediate heat exchanger between the primary and secondary loops remain scarce. In this work, numerical simulations were conducted to investigate the heat transfer and flow characteristics of LBE and CO2-based mixtures in straight-channel printed circuit heat exchangers (PCHEs). The performance of CO2-propane, CO2-krypton and CO2-xenon at different mixing mole fractions was compared. The results show that, among the investigated CO2-based mixtures, the CO2-propane mixture provides the most favourable heat transfer performance when coupled with LBE. Compared with pure CO2 under the same operating conditions, the overall heat transfer coefficient of the CO2-propane/LBE PCHE increases by up to 40%. In addition, the impact of key parameters (e.g., inlet velocity, mass flow rate, inlet temperature, and pressure) on the heat transfer characteristics of CO2-propane mixtures was analysed. Finally, correlations for the Nusselt number and friction factor were derived using the simulation results, with prediction errors within ±3% for CO2-propane mixtures with a propane mole fraction in the range of 0.05-0.30. This study provides a theoretical foundation for designing and optimizing PCHEs with LBE and CO2-based mixtures serving as heat transfer media.
Date Issued
2026-12-01
Date Acceptance
2026-07-09
Citation
International Journal of Thermal Sciences, 2026, 230
ISSN
1290-0729
Publisher
Elsevier BV
Journal / Book Title
International Journal of Thermal Sciences
Volume
230
Copyright Statement
Copyright © 2026 Elsevier Masson SAS. 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
111183
Date Publish Online
2026-07-16