Conductivity Of Open-cell Foams Research Articles

Novel Mixing Relations for Determining the Effective Thermal Conductivity of Open-Cell Foams.

This paper proposes a new approach to relate the effective thermal conductivity of open-cell solid foams to their porosity. It is based on a recently published approach for estimating the dielectric permittivity of isotropic porous media. A comprehensive assessment was performed comparing the proposed mixing relation with published experimental data for thermal conductivity and with numerical data from state-of-the-art relations. The mixing relation for the estimation of thermal conductivities based on dodecahedrons as building blocks shows good agreement with experimental data over a wide range of porosity.

Conductive properties of foam materials with open or closed cells

The work is devoted to computer simulations of the effective conductive properties of open and closed-cell foam materials. The conductivity of the solid phase of the foam is assumed to be much larger than the one of the filler. For the calculation of the effective conductivity, a complex cell element of the foam that consists of a typical cell and its nearest neighbors is introduced. This element is embedded in the medium with the conductivity of the solid phase. For the calculation of the field and field flux in the complex cell, 3D-integral equations for the fields in heterogenous media are used. The effective conductivity is the coefficient that relates the average field and the field flux in the central part of the complex cell. The method is applied to the calculation of the effective conductivity of open cell foams with various shapes of ligaments. Transition from open to closed-cell foams is considered. Predictions of the method are compared with the experimental data available in the literature.