Numerical study on the effects of drastic variations in thermal conductivity on the supercritical CO2 heat transfer deterioration

Release time:2026-03-10  Hits:

• Impact Factor:4.8
• DOI number:10.1016/j.ijthermalsci.2026.110708
• Journal:INTERNATIONAL JOURNAL OF THERMAL SCIENCES
• Place of Publication:ELSEVIER FRANCE
• Key Words:upercritical CO2; Heat transfer deterioration; Thermal conductivity; Heat transfer mechanism; Buoyancy effect; Flow acceleration
• Abstract:The present study presents a numerical investigation into the heat transfer deterioration (HTD) mechanism during supercritical CO2 flowing upward in a vertical tube, with emphasis on the synergistic role of drastic variations in density and thermal conductivity near the pseudo-critical point. By selectively isolating property variations, the study reveals that abrupt density changes are a primary trigger of HTD, provoking buoyancy-induced flow re-laminarization and flow acceleration that suppress turbulent transport. Furthermore, sharp declines in thermal conductivity are shown to exacerbate HTD through a dual mechanism, that is, impairing heat conduction within the viscous sublayer and intensifying axial thermal gradients, which further amplify buoyancy and acceleration effects. These interactions collectively impair turbulent heat transfer efficiency. The results offer novel understanding of the coupled thermophysical pathways governing HTD and support the optimized design of heat exchange systems in supercritical CO2 power cycles.
• Indexed by:Journal paper
• Document Code:110708
• Discipline:Engineering
• Document Type:J
• Volume:224
• ISSN No.:1290-0729
• Translation or Not:no
• Date of Publication:2026
• Included Journals:SCI、EI