Thermal destratification in a cylindrical packed bed

Abstract

Thermal destratification was observed in a cylindrical packed bed 62 cm high and 37.5 cm in diameter filled with 12.6 mm diameter glass spheres and saturated with air. The boundaries were impermeable and covered with 10.2 cm of either polystyrene or fiberglass insulation except in one experiment where the top surface was free and uninsulated. An apparent thermal diffusivity was calculated from the data assuming conduction only and indicated that natural convection must have a role in thermal destratification. A flow pattern consistent with the measured axisymmetric temperature field suggests that heat transfer through the sides may be important in the destratification process.