The length effect on packed bed effective heat transfer parameters

Abstract

The effective radial thermal conductivity and apparent wall heat transfer coefficient in a packed bed were determined experimentally in a laboratory-scale packed bed heat exchanger. Care was taken to use a thermo-couple support cross made out of low conductivity materials and to measure the wall temperature profile in the calming section. A new model, which took heat leaks into the calming section into account, yielded effective parameters which showed little or no systematic length effects, in contrast to all previous work using two-parameter models. The effective axial thermal conductivity, introduced in previous publications to overcome length effects, was shown to owe its high values to the inadequate experimental elimination of extraneous axial heat transfer.