Analysis of thermal conduction in carbon foams

Carbon foams are a new class of porous organic materials that are being developed for use as insulation, heat spreaders, and compact heat exchanger cores. The thermal conductivity of carbon foams is difficult to determine analytically, particularly for the case of high porosity, graphitic foams that show moderate to high bulk conductivity. Models that predict thermal conductivity of foams often use an empirical parameter to account for the effect of pore shape and material microstructure on the conduction process. A finite element (FEM) analysis has been developed to calculate the thermal conductivity of carbon foams for the complete range of porosity. The results are interpreted in terms of analytical and semi-empirical solutions. It is shown that the FEM solution matches the theoretical solution that is valid for low porosity, but differs significantly from semi-empirical solutions of high porosity foams. (C) 2004 Elsevier SAS. All rights reserved.