Comparison of Heat Transfer Characteristics between Supercritical N-Decane and Supercritical Carbon Dioxide in a Single Square Minichannel

Abstract

Numerical investigations were conducted to analyze the heat transfer characteristics in a single square minichannel with supercritical C₁₀H₂₂ (sC₁₀H₂₂) and supercritical CO₂ (sCO₂). A single symmetric minichannel with a square cross-section of 1 mm × 1 mm and a length of 400 mm was selected, the top surface of which is applied with a uniform heat flux from 100 to 300 kW/m². The inlet temperatures are varied from 20 to 150 °C and the inlet mass fluxes are ranged from 300 to 500 kg/(m²·s) in the physical model. The flow and heat transfer processes of the fluids were simulated in COMOSOL Multiphysics® software with RANS k-ω low-Reynolds number turbulence model. Results show that the heat removal capacity of sCO₂ at 8 MPa is superior, which is 8 times that of sC₁₀H₂₂ at 3 MPa at the inlet temperature of 20 °C. When the inlet temperature and heat flux increase, the heat transfer performance of sCO₂ drops sharply, while the overall performance of sC₁₀H₂₂ rises steadily. It suggests that sCO₂ is more suitable for the heat transfer process with high-efficient cooling system at a lower inlet temperature, while sC₁₀H₂₂ is capable of a stable and long-time heat transfer process at a higher inlet temperature.

Acknowledgments

The authors gratefully acknowledge the financial support from the National Nature Science Foundation of China (No. 11872373 & No. T2221002).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Dongxia Dang

Dongxia Dang received her B.S. degree in Energy and Power Engineering from Tianjin University, Tianjin, China. She is currently studying for a doctor’s degree at the National University of Defense Technology and her current research lies in heat transfer enhancement in micro-scale channels, and engine thermal management technology.

Yuan Wang

Yuan Wang obtained her Ph.D. in Chemical Engineering from the University of Edinburgh in 2011 and joined the National University of Defense Technology. Her research interests include air precooling technology for combined cycle propulsion systems, engine thermal protection, icing and anti-icing, and heat and mass transfer in phase-change processes. She has published over 60 academic papers and has been authorized over 10 national patents. She is selected for the High-level Innovative Talent Training Program of National University of Defense Technology.