Performance enhancement in minichannel heat sinks using supercritical carbon dioxide (sCO2) as a coolant

Awais, Ahmad Ali; Saeed, Muhammad; Kim, Man-Hoe

doi:10.1016/j.ijheatmasstransfer.2021.121539

Cited by 19 publications

(12 citation statements)

References 43 publications

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“…This is also because the density and dynamic viscosity of CO 2 change drastically with temperature near the pseudocritical point, especially density, which is much more sensitive to the temperature compared to the water. Similar conclusions also appeared in [ 30 ].…”

Section: Resultssupporting

confidence: 91%

“…These thermophysical characteristics of CO 2 show the potential to improve flow resistance characteristics while maintaining a heat transfer performance close to that of water. Research in [ 29 , 30 ] both showed that supercritical CO 2 (sCO 2 ) can provide a higher cooling performance with lower channel pressure loss than liquid cooling. Khalesi and Sarunac [ 31 ] conducted a good deal of analyses on the development process and conjugated heat transfer in microchannels using supercritical CO 2 and liquid sodium as coolants.…”

Section: Introductionmentioning

confidence: 99%

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Comparative Study of the Thermal and Hydraulic Performance of Supercritical CO2 and Water in Microchannels Based on Entropy Generation

Zeng

2022

Entropy

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The excellent thermophysical properties of supercritical CO2 (sCO2) close to the pseudocritical point make it possible to replace water as the coolant of microchannels in application of a high heat flux radiator. The computational fluid dynamics (CFD) method verified by experimental data is used to make a comparison of the thermal hydraulic behavior in CO2-cooled and of water-cooled microchannels. The operation conditions of the CO2-based cooling cases cover the pseudocritical point (with the inlet temperature range of 306~320 K and the working pressure of 8 MPa), and the water-based cooling case has an inlet temperature of 308 K at the working pressure of 0.1 MPa. The channel types include the straight and zigzag microchannels with 90°, 120°, and 150° bending angles, respectively. The analysis result shows that, only when the state of CO2 is close to the pseudocritical point, the sCO2-cooled microchannel is of a higher average heat convection coefficient and a lower average temperature of the heated surface compared to the water-cooled microchannel. The entropy generation rate of the sCO2-cooled microchannel can reach 0.58~0.69 times that of the entropy generation rate for the water-cooled microchannel. Adopting the zigzag structure can enhance the heat transfer, but it does not improve the comprehensive performance represented by the entropy generation rate in the sCO2-cooled microchannel.

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Section: Resultssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Comparative Study of the Thermal and Hydraulic Performance of Supercritical CO2 and Water in Microchannels Based on Entropy Generation

Zeng

2022

Entropy

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“…Consequently, the k − turbulence model is not appropriate for flows with the boundary layer separation, flows with sudden changes in the mean streamflow, flows in revolving fluids, and flows over curved surfaces. On the other hand, the shear stress turbulence (SST) model combines two models [19][20][21][22][23][24][25], i.e., k − ω and k − turbulence models according to the distance from the wall. Wilcox k − ω is utilized to resolve the flow in the vicinity of the walls for accurate prognostication of the boundary layer, whereas the k − turbulence model is solving the flow in fully developed regions to gain advantage from its robustness, economy, and free stream independence [13,19].…”

Section: Computational Model 21 Governing Equationsmentioning

confidence: 99%

Evaluation of the Erosion Characteristics for a Marine Pump Using 3D RANS Simulations

et al. 2021

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In the present study, an erosion analysis of an industrial pump’s casing and impeller blades has been performed computationally. Effects of various critical parameters, i.e., the concentration and size of solid particles, exit pressure head, and cavitation on the erosion rate density of the casing and blade have been investigated. Commercial codes CFX, ICEM-CFD, and ANSYS Turbogrid are employed to solve the model, mesh generation for the casing, and mesh generation of the impeller, respectively. The Eulerian-Eulerian method is employed to model the pump domain’s flow to solve the two phases (water and solid particles) and the interaction between the phases. Published experimental data was utilized to validate the employed computational model. Later, a parametric study was conducted to evaluate the effects of the parameters mentioned above on the erosion characteristics of the pump’s casing and impeller’s blade. The results show that the concentration of the solid particles significantly affects the pump’s erosion characteristics, followed by the particle size and distribution of the particle size. On the other hand, the exit pressure head and cavitation do not affect the erosion rates considerably but significantly influence the regions of high erosion rate densities.

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“…In addition, the supercritical operating pressure makes it not easy and convenient to study the sCO 2 heat transfer performance experimentally, so many researchers have also developed some numerical research in this area. 18,[30][31][32][33] For example, Du et al 30 studied the sCO 2 cooling heat transfer performance in a 6 mm tube by numerical simulation. It showed that the turbulence flow was dramatically affected by buoyancy and the sCO 2 cooling heat transfer was enhanced.…”

Section: Introductionmentioning

confidence: 99%

“…However, in large diameter horizontal tubes, the buoyancy effect only slightly enhanced the sCO 2 turbulent heat transfer. Awais et al 33 employed numerical simulation method to analyze the sCO 2 cooling performance in a minichannel under different inlet pressures and temperatures. Tian et al 34 conducted numerical investigation in horizontal tubes to study the mixing convection heat transfer when the working pressure is at supercritical pressure, and analyzed the influence of buoyancy, property variations, working pressure, and the diameter of the inner‐tube on the heat transfer.…”

Section: Introductionmentioning

confidence: 99%

Comparison and evaluation of supercritical CO ₂ cooling performance in horizontal tubes with variable cross‐section by field synergy theory

Hao

et al. 2022

Intl J of Energy Research

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Summary The cooling/heating performance improvement of supercritical carbon dioxide (sCO2) in heat exchange tube with changing cross‐section is significant and crucial for solar‐driven advanced thermal systems' application and development. The study introduced and constructed straight, diverging, and converging horizontal tubes with the changing cross‐section. The analyzation and evaluation of the sCO2 cooling performance used the combination of SST k‐ω turbulence model‐based numerical method and the field synergy theory, including the influence of tube cross‐sectional shape, inlet pressure and temperature on the cooling performance. As these simulation results indicate, the converging tube can enhance the flow field's synergy and increase the heat transfer ability by 13.15% under cooling conditions. Nevertheless, the heat transfer ability of the sCO2 decreases in the diverging tube under cooling conditions. Besides, the total heat transfer rate rises and the surface heat transfer coefficient has the opposite trends when the inlet temperature increases. Meanwhile, when inlet pressure varies from 11 to 12 MPa, the total heat exchange and surface convective heat transfer coefficient are the maximum. In conclusion, a converging horizontal tube and a suitable inlet pressure can effectively improve the cooling performance of the sCO2. The converging cross‐section design will provide an alternative for its application in advanced thermal systems.

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Performance enhancement in minichannel heat sinks using supercritical carbon dioxide (sCO2) as a coolant

Cited by 19 publications

References 43 publications

Comparative Study of the Thermal and Hydraulic Performance of Supercritical CO2 and Water in Microchannels Based on Entropy Generation

Comparative Study of the Thermal and Hydraulic Performance of Supercritical CO2 and Water in Microchannels Based on Entropy Generation

Evaluation of the Erosion Characteristics for a Marine Pump Using 3D RANS Simulations

Comparison and evaluation of supercritical CO ₂ cooling performance in horizontal tubes with variable cross‐section by field synergy theory

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Performance enhancement in minichannel heat sinks using supercritical carbon dioxide (sCO2) as a coolant

Cited by 19 publications

References 43 publications

Comparative Study of the Thermal and Hydraulic Performance of Supercritical CO2 and Water in Microchannels Based on Entropy Generation

Comparative Study of the Thermal and Hydraulic Performance of Supercritical CO2 and Water in Microchannels Based on Entropy Generation

Evaluation of the Erosion Characteristics for a Marine Pump Using 3D RANS Simulations

Comparison and evaluation of supercritical CO 2 cooling performance in horizontal tubes with variable cross‐section by field synergy theory

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Comparison and evaluation of supercritical CO ₂ cooling performance in horizontal tubes with variable cross‐section by field synergy theory