Effect of packing conditions and materials properties on loose packing fraction of rigid particles: a theoretical and experimental review

Abstract

This paper focuses on the effect of packing conditions and materials properties on loose packing fraction of particles from theoretical and experimental perspectives. First, the difference in loose packing of particles was measured in different conditions. In the second part, we obtained the main factor that dominated the loose packing fraction in different particle scales. We concluded that kinetics energy induced by the gravitational potential energy almost has no influence on the loose packing fraction for particles smaller than a few millimeters. On the contrary, the wall effect became more and more evident with the increase of particle size. Particle morphology and PSD significantly affect the loose packing of particles above the sub-millimeter size. Moreover, for micron-sized particles, the Van der Waals force was shown to dominate all other colloidal interactions, and the ratio between Van der Waals force and effective gravity determined the loose packing fraction of fine powders.