Calculation of thermal conductivity of foamed material

For thermal insulation in buildings and technical installations at the present time homogenous heavy clay bodies are being developed which are provided with a large number of small pores by means of foam pore-forming together with conventional pore-forming. In this paper relationships are drawn up which permit the calculation of the thermal conductivity of the foamed material, based on the properties of the solid and simplified assumptions on the geometry of the pore microstructure. The pores are taken as approximately cubic in shape. A mono-pore forming and double pore size model are presented and analysed. The calculated relationship between the bulk density and the thermal conductivity is in principle in good correlation with equivalent measurement data. The influence of necessary simplifications in the model is allowed for by means of an adaptation factor. The equations are suitable for porosities of over about 80-85%.