The effects of physical factors on the granular hopper flow

Abstract

The flowing behavior of granular materials is known as granular flow, which is ubiquitous in nature, industry and daily life. The behavior is not only related to flowing particles’ properties such as size, shape, density, and coarseness, but also to the external environments such as the flow channel and outlet. Therefore, the granular flow exhibits abundant non-linear phenomena. By now, great achievements have been made in the engineering field, but a unified theoretical framework is still absent. Consequently, it is very necessary to systemically investigate the effects of different parameters on the granular flow. This will be beneficial to deepen the understanding of flowing behavior, uncover the flowing mechanism, as well as potentially open a new avenue of establishment of the constitutive equations. This paper mainly focuses on the hopper flow including gravity-driven hopper, inclined hopper and velocity-driven horizontal hopper, and presents the dependence of the flow rate, flow pattern, particle velocity and packing fraction on various physical factors. These factors involve the outlet size, outlet position, outlet shape, coefficient of friction of inter-particles, particle shape, outlet number, external stimulus, obstacles, and hopper angle. The results can provide significant reference for tuning the flow rate and transportation efficiency, as well as serve as the basis for the future research.