A numerical study on determination of volume averaged thermal transport properties of metal foam structures using X-ray microtomography technique

Çelik, Hasan; Mobedi, Moghtada; Nakayama, A.; Özkol, Ünver

doi:10.1080/10407782.2018.1494936

Cited by 11 publications

(8 citation statements)

References 18 publications

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“…Nu vH is the channel-based volumetric interfacial heat transfer coefficient and it appears automatically by making the governing equations dimensionless. The relation between Nu v and Nu vH is given by Equation (11). Both Nu v and Nu vH are governing parameters for this problem.…”

Section: Governing Equations and Boundary Conditionsmentioning

confidence: 99%

“…q , h, T w and T f B are heat flux at the wall, interfacial heat transfer coefficient between the wall and fluid phase, wall temperature and bulk fluid temperature, respectively. Using dimensionless temperature given by Equation (11), channel Nusselt number is obtained in terms of bulk temperature:…”

Section: Channel Nusselt Numbermentioning

confidence: 99%

“…Bulk temperature is found by integrating fluid temperature expression given by Equation (19). It should be mentioned that Nu H is channel Nusselt number which is completely different than Nu v and Nu vH defined by Equation (11). It refers to the heat transfer from the wall of the channel to the fluid and it is analytically found from the obtained fluid temperature expression.…”

Section: Channel Nusselt Numbermentioning

confidence: 99%

“…Hence, by controlling of the velocity profile in a channel, it is possible to increase velocity in the critic regions and consequently increase heat transfer in that regions such as regions near the heated wall of the channel or tube. Permeability, thermal dispersion and interfacial heat transfer coefficient of aluminum foams with different pore per inch (PPI) values were studied computationally by Celik et al [10,11].…”

Section: Introductionmentioning

confidence: 99%

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Double-Layer Metal Foams for Further Heat Transfer Enhancement in a Channel: An Analytical Study

2021

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A local thermal non-equilibrium analysis of heat and fluid flow in a channel fully filled with aluminum foam is performed for three cases: (a) pore density of 5 PPI (pore per inch), (b) pore density of 40 PPI, and (c) two different layers of 5 and 40 PPI. The dimensionless forms of fully developed heat and fluid flow equations for the fluid phase and heat conduction equation for the solid phase are solved analytically. The effects of interfacial heat transfer coefficient and thermal dispersion conductivity are considered. Analytical expressions for temperature profile of solid and fluid phases, and also the channel Nusselt number (NuH) are obtained. The obtained results are discussed in terms of the channel-based Reynolds number (ReH) changing from 10 to 2000, and thickness ratio between the channel height and sublayers. The Nusselt number of the channel with 40 PPI is always greater than that of the 5 PPI channel. It is also greater than the channel with two-layer aluminum foams until a specific Reynolds number then the Nusselt number of the channel with two-layer aluminum foams becomes greater than the uniform channels due to the higher velocity in the outer region and considerable increase in thermal dispersion.

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Section: Governing Equations and Boundary Conditionsmentioning

confidence: 99%

Section: Channel Nusselt Numbermentioning

confidence: 99%

Section: Channel Nusselt Numbermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Double-Layer Metal Foams for Further Heat Transfer Enhancement in a Channel: An Analytical Study

2021

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“…For the pore scale study, the continuity and momentum equations are solved to find the velocity and pressure distributions and the energy equations for fluid and solid phases are solved to obtain the solid and fluid temperature distribution. The dimensionless form of governing equations for the pore scale analysis is (Celik et al, 2018b):…”

Section: Governing Equations For Pore Scale Domainmentioning

confidence: 99%

Simulation of heat transfer in a closed-cell porous media under local thermal non-equilibrium condition

Wang

Mobedi

Kuwahara

2019

HFF

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Purpose The purpose of this study is to validate whether the local thermal equilibrium for unsteady state is an appropriate assumption for the porous media with closed pores. It also compares the transient temperatures between the pore scale and volume averaged approaches to prove that the volume averaged method is an appropriate technique for the heat transfer in closed-cell porous media. The interfacial heat transfer coefficient for the closed-cell porous media is also discussed in details. Design/methodology/approach The governing equations for the pore scale and continuum domains are given. They are solved numerically for the pore scale and volume-averaged domains. The results are compared and discussion was done. The performed discussions and explanations are supported with figure and graphics. Findings A local thermal non-equilibrium exits for the closed-cell porous media in which voids are filled with water during the unsteady heat transfer process. Local thermal non-equilibrium condition exists in the cells under high temperature gradient and it disappears when the heat transfer process becomes steady-state. Although a local thermal equilibrium exists in the porous media in which the voids are filled with air, a finite value for heat transfer coefficient is found. The thermal diffusivity of air and solid phase are close to each other and hence a local thermal equilibrium exists. Research limitations/implications The study is done only for the closed-cell porous media and for Rayleigh number till 105. Two common working fluids as water and air are considered. Practical implications There are many applications of porous media with closed pores particularly in the industry, such as the closed-cell metal foam or the closed cells in porous materials such as foods and plastic-based insulation material. The obtained results are important for transient heat transfer in closed-cell porous materials. Social implications The obtained results are important from the transient application of heat transfer in the closed-cell material existing in nature and industry. Originality/value The authors’ literature survey shows that it is the first time the closed-cell porous media is discussed from local thermal non-equilibrium point of view and it is proved that the local thermal non-equilibrium can exist in the closed-cell porous media. Hence, two equations as solid and fluid equations should be used for unsteady heat transfer in a closed-cell porous medium.

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A review on thermal application of metal foam

Chen

Guo

Wang

2020

Sci. China Technol. Sci.

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A numerical study on determination of volume averaged thermal transport properties of metal foam structures using X-ray microtomography technique

Cited by 11 publications

References 18 publications

Double-Layer Metal Foams for Further Heat Transfer Enhancement in a Channel: An Analytical Study

Double-Layer Metal Foams for Further Heat Transfer Enhancement in a Channel: An Analytical Study

Simulation of heat transfer in a closed-cell porous media under local thermal non-equilibrium condition

A review on thermal application of metal foam

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