@article{DENG2026, 
author = {Guangzhe DENG and Fei YU and Chao YUAN},
title = {Mechanism and experimental study of supercritical CO2-water coupled heat transfer},
year = {2026},
journal = {Journal of Chongqing University},
volume = {49},
number = {4},
pages = {63-80},
keywords = {supercritical CO2, CO2-water coupled heat transfer, phase-change energy enhancement, thermal power exchange, thermal-hydraulic-solid coupling},
url = {https://www.sciopen.com/article/10.11835/j.issn.1000-582X.2024.282},
doi = {10.11835/j.issn.1000-582X.2024.282},
abstract = {Under the background of the “dual carbon” goals, exploring new pathways for industrial restructuring, reducing carbon emissions, improving energy efficiency, and developing new high-quality productivity for CO2 high-energy utilization has become a research focus. To determine the mechanism of CO2 phase-change-induced cracking and expand its engineering applications, this study investigates the safety and environmental advantages of CO2 based on its multiphase characteristics and energy-utilization potential. A numerical gas-water coupling model is established. Using CO2 at 25 ℃ as the research object, a simulation scheme is designed to examine different water temperatures as heat-carrying fluids, thereby revealing the CO2-water heat-transfer mechanism under hydrothermal-CO2 coupling. Furthermore, the heat and mass transfer characteristics of two-phase flow are analyzed by a CO2-water enhanced tube-type heat-exchanger test. The results show that as the hydrothermal-fluid temperature increases, the CO2 heating rate increases proportionally: for every 1 ℃ increase in water temperature, CO2 temperature increases by 0.9 ℃. The water-stream temperature gradually decreases as CO2 absorbs heat, and the dissipation temperature of the hydrothermal fluid is proportional to the CO2 absorption temperature. The heat-transfer coefficient of the hydrothermal fluid increases from 1790 W/(m2·K) to 2090 W/(m2·K) and continues to rise with higher initial water temperatures. The heat transfer coefficient of CO2 is positively correlated with that of the hydrothermal fluids. The CO2 phase-change heat-absorption temperature shows an exponential growth trend with increasing water temperature. The maximum internal CO2 pressure increases from 131 MPa to 199 MPa, undergoing sequential stages: thermal expansion of liquid CO2, thermal expansion of gaseous CO2, phase-change energization, and pressure stabilization. CO2 heat absorption is positively correlated with the initial water temperature, and the thermal power of the water-flow heat source increases with rising water temperature. The effectiveness of supercritical CO2-water convective heat transfer is verified through the establishment of correlation equations and experimental analysis. This research provides significance theoretical and engineering insights for energy-conversion applications under non-uniform heat-flow conditions, such as photothermal systems, boilers, and CO2 fracturing and storage.}
}