Characterization of non-Newtonian rheological behaviors of powders

Rheological study of powder flow is a hot topic in recent years. This paper aims to provide a novel alternative method for powder rheological characterization, instead of the conventional melt rheology. To achieve this goal, powders including glass beads, pulverized coal and alumina with different particle sizes were used as experimental materials. Powder flow properties were determined in terms of angle of repose, Hausner ratio, Carr's flowability index and permeability. Further, powders were discharged from the pressurized hopper to evaluate the effect of differential pressure on powder flow. The relationship between the differential pressure and the particle velocity was analyzed to reveal the non-Newtonian rheological behaviors of powders, which were further discussed from the perspective of the flow behavior index and the consistency coefficient. Based on the multivariate nonlinear regression analysis of the data, the flow behavior index was related to powder physical parameters and flow parameters, and the predictions agreed well with the experimental results. This study may provide a simple and feasible method for the rheological characterization of powder.