The effective thermal properties of solid foam beds: Experimental and estimated temperature profiles

The effective radial heat conductivity of a solid foam packing and the wall heat transfer coefficient are determined under fluid flow conditions typical of catalytic reactors. A detailed 2-D heterogeneous model is phase-averaged in order to rigorously define lumped heat transfer parameters. The resulting pseudo-homogeneous model involves two fitting parameters only and it is successfully compared with experiments. First, experiments with packed extrudates validate the approach in comparison with known results. A second experiment with solid foams (polyurethane and SiC) allows correlating the radial heat conductivity to the nature of the solid, its morphology and fluid flow characteristics. The method is inspired from the correlations for particles and seems very promising. Conversely, determining the wall heat transfer coefficient yields only an average value (110W m(-2) K-1 +/- 15%) and correlation with fluid velocity is impossible in the studied range 0.018-0.32 m s(-1). (C) 2010 Elsevier Ltd. All rights reserved.