  A multiscale model of open-cell foams is developed for the characterization
of heat exchangers. The model is applicable to a wide range of materials, cell
sizes, and porosities. The microscopic geometry is based on a periodic model
that is defined by the porosity and the specific surface area of the foam
considered. The representative geometrical scales of the model are validated
with microscope images and computed tomography scans. The outputs of the
microscopic model are the coefficients of the parabolic pressure loss curve,
the thermal conductivity, and the Nusselt number. These values are used as
inputs of the macroscopic model that determines the thermal performance of a
macroscopic system. The results given by the models are compared with
experimental data obtained from the literature, and from an experimental setup
built at CERN. It is concluded that the multiscale model provides accurate
results in all open-cell foams considered.
