Abstract
Based on the model of a fixed bed as a series of perfect mixers, a factor is derived for correcting the logarithmic mean driving potentials in the conventional plug‐flow equations for fluid‐particle heat and mass transfer in packed beds. This factor, which accounts for axial mixing and is a measure of the transfer efficiency of the bed relative to the idealized case where axial mixing is absent, increases towards unity with bed height but decreases with ratio of terminal driving potentials.