Experimental and computational study of a flighted rotary drum cross-sectional characteristics

The current work involves experimental and computational study of rotary drum cross-sectional characteristics such as: kinetic angle of repose (AoR), flight holdup, flight geometry and flight discharge energy. Experiments with two spherical and three non-spherical particulate materials with sizes between 70 μm and 2 mm were performed in a home-made rotary drum to measure the kinetic angle of repose as a function of flight angular position and drum rotational speed. As a result, an empirical model was proposed to predict the kinetic AoR as a function of the Archimedes number (Ar), Froude number (Fr), and flight angular position. The kinetic AoR predicted by the model is fairly correlated with the experimental findings, with an error of ±8%. The effect of moisture was also examined for a single case of material type and percentage of moisture content, and the results indicated that the same model for dry material can be applied to moist material. In addition, a simple computational algorithm was introduced to predict the flight holdup for any angular position of the flight. Validation using experimental data from the literature demonstrated the soundness of the model. Furthermore, a discharge energy characteristic was introduced, and a parametric study showed that this characteristic can be used as a new key parameter for optimization purposes.