Laminar convective heat transfer of supercritical CO2 in horizontal miniature circular and triangular tubes

Cao, Xianlong; Rao, Zhenghua; Liao, Shengming

doi:10.1016/j.applthermaleng.2011.03.038

Cited by 68 publications

(18 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Jiang et al studied supercritical CO 2 buoyancy in porous media and vertical minitubes. Liao et al determined that the influences of buoyancy are substantial for flow orientations and demonstrated that the tube diameter influences the relationship between the buoyancy effects and the Nusselt number. He et al observed that the heat transfer mode does not substantially affect buoyancy parameters and that forced convection is the mode of heat transfer in vertical minitubes.…”

Section: Introductionmentioning

confidence: 99%

Effect of heat extraction optimization with supercritical carbon dioxide on transcritical power cycle

Hsieh

2020

Int J Energy Res

View full text Add to dashboard Cite

An experimental and thermodynamic analysis was conducted to explore the match in operating conditions for the heat extraction of supercritical CO 2 and the CO 2 transcritical organic Rankine cycle (CTORC). The results revealed that in the optimal conditions of the experiment, the difference between the pseudocritical temperature and the inlet temperature (ΔT pc − in ) was <10 K and T b /T pc (ratio of the bulk temperature to the pseudocritical temperature) was ≤1 (ideal scenario: T b /T pc = 1). Furthermore, the heat transfer and fluid flow of CO 2 as well as the CTORC system performance at the optimal T b /T pc could be simultaneously improved with respect to those at ΔT pc − in < 10 K.The peak values of system efficiency for the inlet temperature of the expander of 100 C and 150 C were 5.1% at 12.5 MPa and 8.0% at 17 MPa, with the corresponding T b /T pc being 1.24 (T pc of 55.9 C) and 1.45 (T pc of 70 C), respectively. Consequently, to simultaneously improve the heat transfer, fluid flow and system efficiency, T pc of the supercritical CO 2 in the CTORC should be sufficiently high to approach half the inlet temperature of the expander for obtaining an optimal T b /T pc at a low condensing temperature. K E Y W O R D Sbuoyancy, enhanced geothermal system, heat transfer, pressure drop, supercritical CO 2 , thermodynamic analysis, transcritical organic Rankine cycle

show abstract

Section: Introductionmentioning

confidence: 99%

Effect of heat extraction optimization with supercritical carbon dioxide on transcritical power cycle

Hsieh

2020

Int J Energy Res

View full text Add to dashboard Cite

show abstract

“…Accordingly, supercritical CO 2 is used as a novel refrigerant in mobile air‐conditioners and geothermal heat pumps. The thermal behaviors of supercritical CO 2 in the tube have been widely investigated experimentally and numerically …”

Section: Introductionmentioning

confidence: 99%

“…Besides these experiments, the numerical technology using computational fluid dynamic codes was also used to simulate the thermal behaviors of supercritical CO 2 in the tube. Cao et al numerically discussed flow patterns and thermal behaviors of supercritical CO 2 in the circular/triangular microtube . Li and Jiang simulated the thermal behaviors of supercritical CO 2 in the vertical tube using different turbulent models .…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of flow and heat transfer between supercritical CO₂ tube and flue gas

Wang

Dong

Xue

et al. 2019

Asia-Pacific J Chem Eng

View full text Add to dashboard Cite

To further improve the thermal efficiency of the coal-fired boiler, lower environment restraints, and minimize key components, the supercritical CO 2 Brayton cycle was considered to replace the conventional steam Rankine cycle.In this paper, a three-dimensional mathematical model of the thermal behaviors between the supercritical CO 2 tube and flue gas was established using the Lam-Bremhorst k-ε model, the gas real model, and the P-1 radiation model. The distributions of the velocity and the temperature between the supercritical CO 2 tube and flue gas were investigated numerically. Furthermore, the effects of the supercritical CO 2 inlet temperature on the thermal behaviors were also examined. The results show the surface heat transfer coefficient goes up with the supercritical CO 2 inlet temperature due to the rise of the thermal conductivity. More significant thermal behaviors and detailed physical explanations were elaborated, which would offer a novel insight to understand, design, and optimize the supercritical CO 2 Brayton cycle for engineering applications.

show abstract

“…The authors mainly focused on flows with relatively low Reynolds numbers. Cao [21] and Du [22] numerically studied the convective heat transfer of supercritical CO 2 in horizontal miniature circular and triangular tubes.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Investigation of Convective Heat Transfer of Supercritical Carbon Dioxide at Low Mass Fluxes

Lei

Zhang

et al. 2017

Applied Sciences

View full text Add to dashboard Cite

Featured Application: Supercritical carbon dioxide Brayton cycle, geothermal system, nuclear reactor.Abstract: Significant differences in the heat transfer behaviors of supercritical carbon dioxide in a heated channel have been observed at different mass fluxes. At low mass fluxes, a unique heat transfer characteristic is accompanied by a monotonously smooth temperature variation without any temperature peak, even though the ratio of heat flux to mass flux (q/G) is high. In this study, experimental and numerical investigations explore the hidden mechanism of the peculiar heat transfer characteristics of supercritical carbon dioxide at low mass fluxes in vertically upward tubes with inside diameters (ID) of 5 mm. The range of operating conditions examined within the study include a mass flux (G) between 0-200 kg/m 2 s, and a heat flux (q) of up to 120 kW/m 2 . The parametric effects within these experimental conditions were analyzed on the basis of the obtained heat transfer data. Furthermore, a qualitative modeling force analysis and quantitative numerical simulation of vertical flow at low mass flux reveal the heat transfer mechanism for these temperature profiles. In addition, the distribution of flow parameters and thermo-physical properties (such as shear stress, density, and specific heat) in the near-wall region were also studied. It is found that the heat transfer behavior of supercritical CO 2 at low mass flux is similar to "film boiling" at subcritical pressure, where "vapor-like" fluid occupies the sublayer region. Due to reduced buoyancy, the fluid does not cause enough mixing/instability to bring it to the bulk flow.

show abstract

Laminar convective heat transfer of supercritical CO2 in horizontal miniature circular and triangular tubes

Cited by 68 publications

References 16 publications

Effect of heat extraction optimization with supercritical carbon dioxide on transcritical power cycle

Effect of heat extraction optimization with supercritical carbon dioxide on transcritical power cycle

Numerical simulation of flow and heat transfer between supercritical CO₂ tube and flue gas

Experimental and Numerical Investigation of Convective Heat Transfer of Supercritical Carbon Dioxide at Low Mass Fluxes

Contact Info

Product

Resources

About

Laminar convective heat transfer of supercritical CO2 in horizontal miniature circular and triangular tubes

Cited by 68 publications

References 16 publications

Effect of heat extraction optimization with supercritical carbon dioxide on transcritical power cycle

Effect of heat extraction optimization with supercritical carbon dioxide on transcritical power cycle

Numerical simulation of flow and heat transfer between supercritical CO2 tube and flue gas

Experimental and Numerical Investigation of Convective Heat Transfer of Supercritical Carbon Dioxide at Low Mass Fluxes

Contact Info

Product

Resources

About

Numerical simulation of flow and heat transfer between supercritical CO₂ tube and flue gas