LAUSR

Abstract A hopper has very wide and vital applications in handing the granular materials in daily life and industrial production, and the full understanding of the granular flow inside a hopper is of great importance to control and optimize the discharge process. By employing experimental and numerical methods, the influence of particle packed pattern on the transient granular flow is investigated in terms of the particle-scale kinetics and structure. For the mono-sized particles packed pattern, despite the similar particle-scale structure, smaller particles achieve greater kinetic energy conversion efficiency, which helps shorten the discharge time. For the binary-sized particles uniform mixing pattern, the interaction between particles increases the individual kinetic energy and transient average coordination number (CN) of large particles, while decreases that of small ones. Then the in-between kinetic energy and the disperse structure are reached. For the layer by layer mixing pattern, the strong percolation effect caused by the upper small particles hinders the increase of the individual kinetic energy at the beginning of the discharge process, and the transient average CN at the layer interface abruptly reaches 8. By contrast, when the small particles are placed at the bottom, more particles are active in the larger space, and subsequently, a looser structure is achieved in a shorter period.