THERMAL CONDUCTIVITY OF CERAMIC SPONGES AT TEMPERATURES UP TO 1000 °C

This publication reports about high temperature heat transfer in ceramic sponges. Ceramic sponges are opencelled solid network structures with advantageous properties: low pressure drop, high specific surface area, comparatively high heat transfer and good cross mixing in the fluid. For designing technical equipment a socalled homogeneous model for calculating the heat transport inside the sponges can be used. The key parameter for this model is the two-phase thermal conductivity (also often called effective thermal conductivity). In this contribution experimental results for the two-phase thermal conductivity with and without flow for different Al2O3 sponge types are presented. The temperature was varied up to 1000°C, where thermal radiation has to be considered as one important heat transfer mechanism. The results were correlated enabling the estimation of heat transfer in any sponges.