AbstractThe influence of different internal geometries on the solid flow in rotary drums under variation of the operational parameters feed rate, slope, and rotational speed is investigated. Four different configurations of a fully optically accessible lab‐scale rotary drum are analyzed. The internals are built as sectional compartments of the cross section, referring to industrial applications. The axial dispersion model is used to calculate the mean residence times and axial dispersion coefficients. It can clearly be shown that the sectional internal geometries significantly increase mean residence times and holdups in dependence on the set of operational variables. The axial dispersion coefficients were in a comparable range with literature data.