Experimental investigation of convection heat transfer of CO{sub 2} at supercritical pressures in a vertical circular tube

Journal Article · Mon Nov 15 00:00:00 EST 2010 · Experimental Thermal and Fluid Science

DOI:https://doi.org/10.1016/J.EXPTHERMFLUSCI.2010.04.005· OSTI ID:21350386

Li, Zhi-Hui; Jiang, Pei-Xue; Zhao, Chen-Ru; Zhang, Yu ^[1]

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1. Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China)

The convection heat transfer characteristics of supercritical CO{sub 2} in a vertical circular tube of 2 mm inner diameter were investigated experimentally for pressures ranging from 78 to 95 bar, inlet temperatures from 25 to 40 C, and inlet Reynolds numbers from 3800 to 20,000. The effects of the heat flux, thermo-physical properties, buoyancy and thermal acceleration on the convection heat transfer were analyzed. The experimental results show that for high inlet Reynolds numbers (e.g. Re = 9000) and high heat fluxes, a significant local deterioration and recovery of the heat transfer was found for upward flows but not for downward flows. Comparison of the experimental data for inlet Reynolds numbers from 3800 to 20,000 with some well-known empirical correlations showed large differences especially when the heat transfer deteriorates and then recovers when the effect of buoyancy is significant. The experimental data was used to develop modified local turbulent Nusselt number correlations for supercritical CO{sub 2} flowing in vertical small circular tubes. (author)

• OSTI ID: 21350386
• Journal Information: Experimental Thermal and Fluid Science, Vol. 34, Issue 8; Other Information: Elsevier Ltd. All rights reserved; ISSN 0894-1777
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
CONVECTION
CARBON DIOXIDE
EXPERIMENTAL DATA
REYNOLDS NUMBER
TUBES
CORRELATIONS
COMPARATIVE EVALUATIONS
HEAT FLUX
NUSSELT NUMBER
THERMODYNAMIC PROPERTIES
CARBON DIOXIDE COOLED REACTORS
SUPERCRITICAL STATE
PRESSURE RANGE MEGA PA 01-10
TEMPERATURE RANGE 0273-0400 K
Supercritical pressures
Buoyancy
Thermal acceleration
Empirical correlations