Thermal Conductivity Measurement of Bulk Solids and Powder Beds

The thermal conductivity of bulk solids and powder beds are very important for process calculations in drying and packed beds. The moisture content and state of compaction of the bed are important parameters determining the thermal conductivity value, but have seen less attention in the literature. In this work, a simple, easy to use unsteady state thermal conductivity apparatus was developed. Results from this apparatus will be presented for a wide variety of common bulk solids as a function of state of compaction and moisture content. In addition, results will be shown for salts which have formed a dense bulk solid (like a rind of solid often seen in dryers). The experimental results are compared to the combined series/parallel model of Krischer.