A mathematical model for the dynamic angle of repose of a granular material in the rotating drum

This study introduces a mathematical model to predict the dynamic angle of repose exhibited by granular materials in a rotating drum. The model accounts for the effect of particle properties, particularly sliding and rolling friction, as well as process conditions, i.e., the Froude number. We show that the effects of particle properties can be modeled independently of the process conditions, resulting in a multiplicative model. The model is validated using experimental data taken at different Froude numbers, yielding favorable agreement between the predicted dynamic angle of repose and the experimental observations. The findings of this study hold significant implications for engineering disciplines, as they provide crucial insights for optimizing processes involving granular materials in various engineering applications.