Simulation of Thermal Transport in Open-Cell Metal Foams: Effect of Periodic Unit-Cell Structure

Direct simulation of thermal transport in open-cell metal foams is conducted using different periodic unit-cell geometries. The periodic unit-cell structures are constructed by assuming the pore space to be spherical and subtracting the pore space from a unit cube of the metal. Different types of packing arrangement for spheres are considered—body centered cubic, face centered cubic, and the A15 lattice (similar to a Weaire-Phelan unit cell)—which give rise to different foam structures. Effective thermal conductivity, pressure drop, and Nusselt number are computed by imposing periodic boundary conditions for aluminum foams saturated with air or water. The computed values compare well with existing experimental measurements and semiempirical models for porosities greater than 80%. The effect of different foam packing arrangements on the computed thermal and fluid flow characteristics is discussed. The capabilities and limitations of the present approach are identified.

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Simulation of Thermal Transport in Open-Cell Metal Foams: Effect of Periodic Unit Cell Structure

Heat Transfer, Volume 1 ◽

10.1115/imece2006-14044 ◽

2006 ◽

Cited By ~ 2

Author(s):

Shankar Krishnan ◽

Suresh V. Garimella ◽

Jayathi Y. Murthy

Keyword(s):

Thermal Transport ◽

Pore Space ◽

Cell Structure ◽

Flow Characteristics ◽

Metal Foams ◽

Unit Cube ◽

Unit Cell ◽

Face Centered Cubic ◽

Open Cell ◽

Periodic Unit Cell

Direct simulation of thermal transport in open-cell metal foams is conducted using different periodic unit cell geometries. The periodic unit cell structures are constructed by assuming the pore space to be spherical and subtracting the pore space from a unit cube of the metal. Different types of packing arrangement for spheres are considered - Body Centered Cubic, Face Centered Cubic, and the A15 lattice (similar to a Weaire-Phelan unit cell) - which give rise to different foam structures. Effective thermal conductivity, pressure drop and Nusselt number are computed by imposing periodic boundary conditions for aluminum foams saturated with air or water. The computed values compare well with existing experimental measurements and semi-empirical models for porosities greater than 80%. The effect of different foam packing arrangements on the computed thermal and fluid flow characteristics is discussed. The capabilities and limitations of the present approach are identified.

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Direct Simulation of Transport in Open-Cell Metal Foam

Journal of Heat Transfer ◽

10.1115/1.2227038 ◽

2006 ◽

Vol 128 (8) ◽

pp. 793-799 ◽

Cited By ~ 145

Author(s):

Shankar Krishnan ◽

Jayathi Y. Murthy ◽

Suresh V. Garimella

Keyword(s):

Metal Foam ◽

Flow Characteristics ◽

Local Heat Transfer ◽

Local Heat ◽

Unit Cell ◽

Computational Time ◽

Small Scale ◽

Direct Simulation ◽

Open Cell ◽

Periodic Unit Cell

Flows in porous media may be modeled using two major classes of approaches: (a) a macroscopic approach, where volume-averaged semiempirical equations are used to describe flow characteristics, and (b) a microscopic approach, where small-scale flow details are simulated by considering the specific geometry of the porous medium. In the first approach, small-scale details are ignored and the information so lost is represented in the governing equations using an engineering model. In the second, the intricate geometry of the porous structures is accounted for and the transport through these structures computed. The latter approach is computationally expensive if the entire physical domain were to be simulated. Computational time can be reduced by exploiting periodicity when it exists. In the present work we carry out a direct simulation of the transport in an open-cell metal foam using a periodic unit cell. The foam geometry is created by assuming the pore to be spherical. The spheres are located at the vertices and at the center of the unit cell. The periodic foam geometry is obtained by subtracting the unit cell cube from the spheres. Fluid and heat flow are computed in the periodic unit cell. Our objective in the present study is to obtain the effective thermal conductivity, pressure drop, and local heat transfer coefficient from a consistent direct simulation of the open-cell foam structure. The computed values compare well with the existing experimental measurements and semiempirical models for porosities greater than 94%. The results and the merits of the present approach are discussed.

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Direct Simulation of Transport in Open-Cell Metal Foams

Heat Transfer, Part B ◽

10.1115/imece2005-81309 ◽

2005 ◽

Cited By ~ 5

Author(s):

Shankar Krishnan ◽

Jayathi Y. Murthy ◽

Suresh V. Garimella

Keyword(s):

Metal Foam ◽

Flow Characteristics ◽

Local Heat Transfer ◽

Local Heat ◽

Unit Cell ◽

Small Scale ◽

Direct Simulation ◽

Open Cell ◽

Semi Empirical ◽

Periodic Unit Cell

Flows in porous media may be modeled using either a macroscopic approach, where volume-averaged semi-empirical equations are used to describe flow characteristics, or a microscopic approach, where small-scale flow details are simulated by considering the specific geometry of the porous medium. A direct simulation of the transport in an open-cell metal foam is carried out in the present study using a periodic unit cell. The foam geometry is created by assuming the pore to be spherical. The spheres are located at the vertices and at the center of the unit cell. The periodic foam geometry is obtained by subtracting the unit cell cube from the spheres. Fluid and heat flow are computed in the periodic unit cell. The objective of the present study is to obtain the effective thermal conductivity, pressure drop and local heat transfer coefficient from a consistent direct simulation of the open-cell foam structure. The computed values compare well with the existing experimental measurements and semi-empirical models. The results and the merits of the present approach are discussed.

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Simulations of flow through open cell metal foams using an idealized periodic cell structure

International Journal of Heat and Fluid Flow ◽

10.1016/j.ijheatfluidflow.2003.08.002 ◽

2003 ◽

Vol 24 (6) ◽

pp. 825-834 ◽

Cited By ~ 185

Author(s):

K. Boomsma ◽

D. Poulikakos ◽

Y. Ventikos

Keyword(s):

Cell Structure ◽

Metal Foams ◽

Open Cell ◽

Periodic Cell ◽

Flow Through

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The Effects of Compression and Pore Size Variations on the Liquid Flow Characteristics in Metal Foams

Journal of Fluids Engineering ◽

10.1115/1.1429637 ◽

2001 ◽

Vol 124 (1) ◽

pp. 263-272 ◽

Cited By ~ 200

Author(s):

K. Boomsma ◽

D. Poulikakos

Keyword(s):

Flow Characteristics ◽

Maximum Flow ◽

Metal Foams ◽

Heat Sinks ◽

Convection Heat ◽

Hydraulic Characteristics ◽

Aluminum Foams ◽

Transitional Regime ◽

Open Cell ◽

Flow Velocities

Open-cell aluminum foams were investigated using water to determine their hydraulic characteristics. Maximum fluid flow velocities achieved were 1.042 m/s. The permeability and form coefficient varied from 2.46×10−10 m2 and 8701 m−1 to 3529×10−10 m2 and 120 m−1, respectively. It was determined that the flowrate range influenced these calculated parameters, especially in the transitional regime where the permeability based Reynolds number varied between unity and 26.5. Beyond the transition regime where ReK≳30, the permeability and form coefficient monotonically approached values which were reported as being calculated at the maximum flow velocities attained. The results obtained in this study are relevant to engineering applications employing metal foams ranging from convection heat sinks to filters and flow straightening devices.

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CFD study on thermal transport in open-cell metal foams with and without a washcoat: Effective thermal conductivity and gas-solid interfacial heat transfer

Chemical Engineering Science ◽

10.1016/j.ces.2016.12.006 ◽

2017 ◽

Vol 161 ◽

pp. 92-108 ◽

Cited By ~ 13

Author(s):

Wenping Peng ◽

Min Xu ◽

Xunfeng Li ◽

Xiulan Huai ◽

Zhigang Liu ◽

...

Keyword(s):

Heat Transfer ◽

Thermal Conductivity ◽

Effective Thermal Conductivity ◽

Thermal Transport ◽

Metal Foams ◽

Interfacial Heat Transfer ◽

Open Cell

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An Analytical Unit Cell Model for the Effective Thermal Conductivity of High Porosity Open-Cell Metal Foams

Transport in Porous Media ◽

10.1007/s11242-014-0281-z ◽

2014 ◽

Vol 102 (3) ◽

pp. 403-426 ◽

Cited By ~ 47

Author(s):

Xiao Hu Yang ◽

Jia Xi Bai ◽

Hong Bin Yan ◽

Jiu Jie Kuang ◽

Tian Jian Lu ◽

...

Keyword(s):

Thermal Conductivity ◽

Effective Thermal Conductivity ◽

Cell Model ◽

Metal Foams ◽

Unit Cell ◽

High Porosity ◽

Unit Cell Model ◽

Open Cell

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Effect of Precursor Design on Preparing Open-Cell Aluminum Foam Fabricated by Space-Holder Method

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1035.169 ◽

2021 ◽

Vol 1035 ◽

pp. 169-174

Author(s):

Tan Wan ◽

Yuan Liu ◽

Fa Ting Xu ◽

Xiang Ding

Keyword(s):

Aluminum Foam ◽

Functional Performance ◽

Cell Structure ◽

Flow Characteristics ◽

Aluminum Foams ◽

Open Cell ◽

Lower Porosity ◽

Negative Effect ◽

Spherical Cells ◽

Good Flow

Open-cell aluminum foams with spherical cells have great potential application due to their reliable structural and functional performance. However, a problem of poor cell connectivity always arises during fabrication. Three precursor designs were explored to optimize the cell structure. The results showed that the lack of the treatment of the space holders caused poor cell connectivity and a lower porosity, which could be resolved by introducing alcohol as a binder or hot-pressing space holders in precursor designs. Nevertheless, a poor fluid of the granules in the former had a negative effect on porosity improvement, whereas the latter created a precursor with strong bonding between the granules with good flow characteristics and led to a significant improvement in cell connectivity and porosity. This work could provide an approach to designing precursor structures in order to tailor the structure of the final open-cell aluminum foam.

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