Convective heat transfer in graphite foams with complex structures

Kai Choong Leong, Hongying Li, Liwen Jin, John C. Chai

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Citations (Scopus)

Abstract

Along with recent advances in electronic packaging, high performance computer processors require more efficient devices for dissipating the high heat fluxes. The use of highly conductive porous media has emerged as an effective cooling method due to its large internal contact surface area which enhances convection at the pore level. In this study, graphite foams developed at Oak Ridge National Laboratory, USA, are used to enhance heat transfer. Initial studies performed by other investigators showed that the extended surface area also results in very high pressure drop for fluid flowing through the graphite foam. This paper presents a numerical and experimental study of convection heat transfer in graphite foams with different structures which are designed to reduce pressure drop. The non local thermal equilibrium model is adopted in the fluid and solid energy equations. The numerical results which are validated by experimental data show that the inlet air flow partially penetrates the designed foam walls and the rest of the air flows tortuously through slots in the structure. Flow mixing is observed in the free stream area inside the structures, which is absent in block graphite foam. This indicates that better convection can be obtained by these structures due to their low flow resistance and high flow velocity. The pressure drop in the designed graphite foam is also found to be significantly lower than that in solid block graphite foam.

Original languageEnglish
Title of host publication2nd International Conference on Thermal Issues in Emerging Technologies, Theory and Applications
Subtitle of host publicationProceedings - ThETA2
PublisherIEEE
Pages419-428
Number of pages10
ISBN (Electronic)9781424435777
ISBN (Print)9781424435760
DOIs
Publication statusPublished - 17 Jul 2009
Externally publishedYes
Event2008 2nd International Conference on Thermal Issues in Emerging Technologies, ThETA 2008 - Cairo, Egypt
Duration: 17 Dec 200820 Dec 2008

Conference

Conference2008 2nd International Conference on Thermal Issues in Emerging Technologies, ThETA 2008
CountryEgypt
CityCairo
Period17/12/0820/12/08

Fingerprint

Foams
Graphite
Heat transfer
Pressure drop
Heat convection
Electronics packaging
Fluids
Air intakes
Flow velocity
Porous materials
Heat flux
Cooling
Air

Cite this

Leong, K. C., Li, H., Jin, L., & Chai, J. C. (2009). Convective heat transfer in graphite foams with complex structures. In 2nd International Conference on Thermal Issues in Emerging Technologies, Theory and Applications: Proceedings - ThETA2 (pp. 419-428). [5167192] IEEE. https://doi.org/10.1109/THETA.2008.5167192
Leong, Kai Choong ; Li, Hongying ; Jin, Liwen ; Chai, John C. / Convective heat transfer in graphite foams with complex structures. 2nd International Conference on Thermal Issues in Emerging Technologies, Theory and Applications: Proceedings - ThETA2. IEEE, 2009. pp. 419-428
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abstract = "Along with recent advances in electronic packaging, high performance computer processors require more efficient devices for dissipating the high heat fluxes. The use of highly conductive porous media has emerged as an effective cooling method due to its large internal contact surface area which enhances convection at the pore level. In this study, graphite foams developed at Oak Ridge National Laboratory, USA, are used to enhance heat transfer. Initial studies performed by other investigators showed that the extended surface area also results in very high pressure drop for fluid flowing through the graphite foam. This paper presents a numerical and experimental study of convection heat transfer in graphite foams with different structures which are designed to reduce pressure drop. The non local thermal equilibrium model is adopted in the fluid and solid energy equations. The numerical results which are validated by experimental data show that the inlet air flow partially penetrates the designed foam walls and the rest of the air flows tortuously through slots in the structure. Flow mixing is observed in the free stream area inside the structures, which is absent in block graphite foam. This indicates that better convection can be obtained by these structures due to their low flow resistance and high flow velocity. The pressure drop in the designed graphite foam is also found to be significantly lower than that in solid block graphite foam.",
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Leong, KC, Li, H, Jin, L & Chai, JC 2009, Convective heat transfer in graphite foams with complex structures. in 2nd International Conference on Thermal Issues in Emerging Technologies, Theory and Applications: Proceedings - ThETA2., 5167192, IEEE, pp. 419-428, 2008 2nd International Conference on Thermal Issues in Emerging Technologies, ThETA 2008, Cairo, Egypt, 17/12/08. https://doi.org/10.1109/THETA.2008.5167192

Convective heat transfer in graphite foams with complex structures. / Leong, Kai Choong; Li, Hongying; Jin, Liwen; Chai, John C.

2nd International Conference on Thermal Issues in Emerging Technologies, Theory and Applications: Proceedings - ThETA2. IEEE, 2009. p. 419-428 5167192.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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N2 - Along with recent advances in electronic packaging, high performance computer processors require more efficient devices for dissipating the high heat fluxes. The use of highly conductive porous media has emerged as an effective cooling method due to its large internal contact surface area which enhances convection at the pore level. In this study, graphite foams developed at Oak Ridge National Laboratory, USA, are used to enhance heat transfer. Initial studies performed by other investigators showed that the extended surface area also results in very high pressure drop for fluid flowing through the graphite foam. This paper presents a numerical and experimental study of convection heat transfer in graphite foams with different structures which are designed to reduce pressure drop. The non local thermal equilibrium model is adopted in the fluid and solid energy equations. The numerical results which are validated by experimental data show that the inlet air flow partially penetrates the designed foam walls and the rest of the air flows tortuously through slots in the structure. Flow mixing is observed in the free stream area inside the structures, which is absent in block graphite foam. This indicates that better convection can be obtained by these structures due to their low flow resistance and high flow velocity. The pressure drop in the designed graphite foam is also found to be significantly lower than that in solid block graphite foam.

AB - Along with recent advances in electronic packaging, high performance computer processors require more efficient devices for dissipating the high heat fluxes. The use of highly conductive porous media has emerged as an effective cooling method due to its large internal contact surface area which enhances convection at the pore level. In this study, graphite foams developed at Oak Ridge National Laboratory, USA, are used to enhance heat transfer. Initial studies performed by other investigators showed that the extended surface area also results in very high pressure drop for fluid flowing through the graphite foam. This paper presents a numerical and experimental study of convection heat transfer in graphite foams with different structures which are designed to reduce pressure drop. The non local thermal equilibrium model is adopted in the fluid and solid energy equations. The numerical results which are validated by experimental data show that the inlet air flow partially penetrates the designed foam walls and the rest of the air flows tortuously through slots in the structure. Flow mixing is observed in the free stream area inside the structures, which is absent in block graphite foam. This indicates that better convection can be obtained by these structures due to their low flow resistance and high flow velocity. The pressure drop in the designed graphite foam is also found to be significantly lower than that in solid block graphite foam.

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Leong KC, Li H, Jin L, Chai JC. Convective heat transfer in graphite foams with complex structures. In 2nd International Conference on Thermal Issues in Emerging Technologies, Theory and Applications: Proceedings - ThETA2. IEEE. 2009. p. 419-428. 5167192 https://doi.org/10.1109/THETA.2008.5167192