The heat transfer at the freeboard surface of the solid bed
was experimentally investigated in a batch rotary drum with a
diameter of 0.6 m and a length of 0.45 m. The change of
temperature at the surface and inside the bed was measured with
Type-K thermocouples and an infrared camera. The
thermocouples are specifically arranged at different radial
distances from the inner wall. Experiments have been done with
a variation of the operational conditions rotational speed from 1
to 6 rpm and filling degree from 5% to 15%. As test materials
glass beads, quartz sand, steel spheres and expanded clay were
used, whereas the impact of particle size and thermo-physical
properties on the heat transport through free bed surface was
analyzed. A characteristic effective thermal conductivity was
defined for the active layer to represent the heat transport from
the free bed surface.
Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016.