Slurry transport in horizontal rotary drums with an end-constriction

Abstract

Transport of sand—water slurries through horizontal rotating drums with an end-constriction was studied. The effects of the slurry feed solids concentration, feed flow rate, drum rotational speed, fluid surface tension, and the presence of lifters on the slurry hold-up, solids concentration and the flow pattern inside the drum were examined. For a drum without lifters, the slurry bed within the drum was found to oscillate. The bed frequency of oscillation was found to be a function of the drum rotational speed. A mathematical model was developed to predict bed frequency of oscillation. Model predictions were in good agreement with the experimental measurements. For a drum with lifters, no slurry bed oscillation was observed. In general, the drum slurry hold-up and solids concentration were dependent on the drum rotational speed. Mean solids concentration in the drum was found to be higher than that in the feed, especially at low feed solids concentrations. The slurry hold-up was found to increase as the slurry feed flow rate was increased. Mean residence time measurements for the solid and fluid phases for both drums showed that the commonly used assumption that the residence times of the two phases are equal is only valid for the sand particles examined at slurry feed concentrations ≥45 vol.%.