Calculation of the Effective Thermal Conductivity of a Metal Hydride Packed Bed

Abstract

The effective thermal conductivity of a metal hydride packed bed was calculated in consideration of the influence of expansion and contraction. The area-contact model was modified so that the porosity and the deformed factor change by expansion and contraction. The porosity was calculated using the experimental formula developed by direct observation. The deformed factor was calculated using assumption of a simple geometrical deformation caused by difference between a particle expansion and a packed bed expansion. The calculation results are consistent with the reported experimental value. The calculation results indicate that the effective thermal conductivity is greatly influenced by the porosity and expansion ratio rather than other parameters. Therefore, this calculation method incorporating the influence of change of packed bed states, which are the porosity and the expansion ratio etc., will be helpful to investigate of heat transfer enhancement on a metal hydride reactor.