Thermal and mechanical analysis of carbon foam

Carbon foams are porous materials which are attractive for many engineering applications because their thermal and mechanical properties can be customized by varying manufacturing process parameters. However, a highly random geometry at pore level makes it very difficult to analyze the properties and the behavior of this material in an application. Published research work on the analysis of foams has employed various ideal geometries to approximate the pore microstructure. However, these models are unable to predict accurately the foam properties and behavior in engineering applications.;The objective of this research work is to determine thermal and mechanical properties of carbon foam on the basis of its true microstructure. A new approach is proposed by creating a three dimensional (3D) solid model based on an accurate representation of the real geometry of carbon foam. Finite element models are then developed to investigate the bulk thermal and mechanical properties of carbon foam using the three dimensional solid model.;On the basis of the true 3D model of carbon foam, a study is undertaken to examine the effect of the unique microstructure on the flow field within the foam pores and the resultant convective heat transfer. A finite volume model is developed using the accurate representation of carbon foam microstructure inside a flow channel. The fluid flow and heat transfer is simulated to evaluate pressure drop and heat transfer capabilities. The carbon foam permeability, inertial coefficient and friction coefficient are determined and found to be in good agreement with experimental and semi-empirical models. The results also show a large enhancement in the heat transfer due to the presence of carbon foam in the channel. These results are comparable to the experimental results available in published literature.;Another application that has been analyzed in this study is the use of carbon foam as tooling material for manufacturing advanced composite materials. Finite element simulations are carried out to predict the process induced residual stresses and deformations when a composite part is manufactured on conventional tooling versus carbon foam tooling. The results show that both the lower coefficient of thermal expansion and the elastic modulus of carbon foam contribute to the reduction of residual stress and deformation of the composite part.