Flow properties of crushed grains as a function of the particle shape

•Particle shape and particle size affect the flowability of crushed grain.•The particle shape is determined by the elongation and the fractionary dimension.•As the flowability decreases, the more the particle shape deviates from spherical shape.•As the elongation increases, tensile strength increases and flowability decreases.•With the enlargement of fractionary dimension the flowability decreases.

The flow properties of bulk materials are influenced by particle shape and particle size, amongst others. Often the particle shape is assumed to be less important in literature. As yet, almost no results are available on the effect of particle shape on the flowability of crushed grain products. Therefore, two test series were performed with two different particle size fractions in the range of 0.2 mm < x < 0.8 mm. To evaluate the flow properties of the particles, the flowability according to Jenike was applied. In the first test series, the flowability was determined by using a Walker shear cell, and in the second test series by means of a translation shear cell according to Jenike. The particle shape was characterized by the ratio of particle length to particle width (elongation) as well as by the fractionary dimension.As the measurements revealed, the flowability of the crushed grain decreased the more the particle shape deviated from the spherical shape and the roughness of the particle surface increased. As the elongation increased, the tensile strength of both particle size fractions increased and the flowability decreased in the first test series. The same behaviour was observed in the second test series where the fractionary dimension was increased.

Graphical abstractFlowability according to Jenike ffc as a function of the central value FF50;0 of the form factor distribution (DM dry matter content).Figure optionsDownload full-size imageDownload as PowerPoint slide