Numerical simulation on thermal properties of closed-cell metal foams with different cell size distributions and cell shapes

In this study, the effect of cell structure on the thermal properties of closed-cell foam metals are studied numerically. To do this, a novel modeling procedure is proposed to generate the FEM foam models with different cell structures. The cell size distribution and cell shape in the established models can be controlled by the modeling parameters applied in the modeling process. Two structural parameters termed as characteristic diameter Dch and characteristic shape anisotropy αch are then introduced to describe the cell size inhomogeneity and cell shape irregularity in the established models. The steady-state heat transfer simulation is carried out to calculate the effective thermal conductivity of foam models. It can be concluded from the simulation results that relative density is not the only factor that influences the thermal properties of closed-cell metal foams. Both the increase of Dch and αch could also induce a reduction in the normalized thermal conductivity. It indicates that, at a given relative density, the foams with the inhomogeneous cell size distribution and irregular cell shape are inclined to have a degraded thermal conductivity. Finally, the underlying mechanism governing the heat transfer behavior is also discussed.