Effects of shear cell size on flowability of powders measured using a ring shear tester

Flowability parameters of powders measured by a shear cell is expected to depend on shear cell size, but details of that effect are lacking. In this work, we have systematically evaluated this using a number of powders under three preshear normal stresses using a ring shear tester. The flowability index (ffc) of a limestone powder (BCR 116) exhibited relatively small differences when measured on three shear cells of different sizes, S (~9.5 cm3) 125 μm. Therefore, one must exercise caution when comparing flow properties of powders characterized using different shear cells. [Display omitted] •Powder flow parameters measured by shear cell testing depend on shear cell size.•Differences in measure flowability parameters tend to be larger for larger particles.•Certifying shear cell with a fine BCR 116 limestone powder does not eliminate the shear cell size effect.•Comparison of flowability parameters determined by different shear cells requires caution.