Rotary drums with sectional internals: Experimental investigation on the influence of section number and section length

Abstract

The impact of sectional internals, as often used in industrial rotary drums, on the axial solid transport in rotary drums is investigated experimentally under variation of the operation parameters solid feed rate, drum inclination and rotational speed. Different section numbers and internal-lengths have been analyzed, applying the axial dispersion model, in a fully optically accessible lab scale rotary drum apparatus.The mean residence times are increasing with the section numbers and their length up to 4 times compared to bare drum results. Capacity limits have been detected, resulting in higher back-spillage ratios dependent on the set of operational parameters. The impacts of parameter changes on the axial dispersion are decreasing with section number and length, resulting in a more constant axial dispersion coefficient of about 1 × 10−6 m2/s. A qualitative similarity of the axial solid bed profile proposed by the Saeman-model for bare drums has been found for sectional internals.