Session: 03-15-03: Multifunctional Materials, Structures and Devices: Modeling, Design, Manufacturing, and Characterization

Paper Number: 77571

Start Time: Thursday, 06:55 PM

77571 - Micromechanical Modeling for Effective Thermal Conductivity of Metallic Foams 

Cellular solid materials are rapidly gaining popularity in applications of thermal energy control,
electric capacitance, and structural efficiency. A number of studies have been conducted to
predict the effective thermal conductivity of metallic foams by using a unit cell-based approach.
The tetrakaidecahedral cell has been commonly adopted as the repeating unit for a three-
dimensional open-cell metallic foam microstructure [1,2]. A temperature difference has been
often applied on two opposing square faces of the cell to generate an overall heat flux
perpendicular to these two faces. However, the orientation of the heat flux could be random in a
real foam structure. This could lead to different measurements of the effective thermal
conductivity, which has usually been attributed to the effect of the manufacturing process. As a
result, there is a need to understand and determine the anisotropy of the effective thermal
conductivity by applying the heat flux along the different orientations of a tetrakaidecahedral
cell.
In this study, a microstructure-based model is developed to predict the effective thermal
conductivity of open-cell metallic foams by using an analogy to electrical conductivity [3]. The
tetrakaidekahedral cell is used as the repeating unit and four typical orientations are considered.
Each ligament contains a straight section with a uniform cross section and two identical joint
sections. Each joint is formed with four identical joint sections. The geometries of the ligaments
are constructed based on the minimum surface energy reached during the foaming process. The
study modularly assesses heat flux through the four orientations of the unit cell, respectively. The
heat flow passages through the unit cell are analyzed and modeled, first analytically, then using
the finite element method to more accurately synthesize the curved facets of the geometric joints.
The numerical results indicate that the effective thermal conductivity of open-cell metallic foams
exhibits some degree of anisotropy. Quantitative results of the model compare favorably well
with those published in open literature.
References
[1] Schmierer, E. N. and Razani, 2006, Self-consistent open-celled metal foam model for thermal
applications, ASME J. of Heat Transfer 128:1194-1206.
[2] Amani, Y., Takahashi, A., Chantrenne, P., Maruyama, S., Dancette, S., and Maire, E.,2018,
Thermal conductivity of highly porous metal foams: experimental and image based finite
element analysis, Int. J. Heat and Mass Transfer 122: 1-10.
[3] Li, H., Li, K., and Gao, X.-L., 2017, A micromechanics model for electrical conductivity of three-dimensional open-
cell metallic foams, IMECE2017-71138, Proceedings of the 2017 ASME International Mechanical Engineering
Congress and Exposition, Nov. 3-9, 2017, Tampa, FL

Presenting Author: Chloe Li Elkins High School

Authors: