Numerical simulations of dense granular flow in a two-dimensional channel: The role of exit position

Abstract

Molecular dynamics simulations have been performed to elucidate the influence of exit position on a dense granular flow in a two-dimensional channel. The results show that the dense flow rate remains constant when the exit is far from the channel wall and increases exponentially when the exit moves close to the lateral position. Beverloo's law proves to be successful in describing the relation between the dense flow rate and the exit size for both the center and the lateral exits. Further simulated results confirm the existence of arch-like structure of contact force above the exit. The effective exit size is enlarged when the exit moves from the center to the lateral position. As compared with the granular flow of the center exit, both the vertical velocities of the grains and the flow rate increase for the lateral exit.

The effects of physical factors on the granular hopper flow

“…图片来源文献 [61], 已获得授权 图 11 (网络版彩图)流量随出口尺寸变化的模拟结果. 正方 形和圆形分别代表中心出口和侧面出口 [62] . 图片来源文献 [62], 已获得授权 [65] .…”

“…Color online) The simulation of flow rate as a function of exit size. The squares and circles indicate the data from an exit located at center of the bottom wall and of the lateral wall, respectively[62]. Reproduced from ref [62].…”

Effect of particle shape on packing fraction and velocity profiles at outlet of a silo

“…The power scaling law between mass flow rate and the opening size has been substantiated in previous studies. [11][12][13][14][15][16][17] A simple explanation of the Beverloo's equation is based on the concept of a "free-fall arch". In this scenario the arch is a surface spanning the exit at a height approximately D away from the exit.…”

Discharge flow of granular particles through an orifice on a horizontal hopper: Effect of the hopper angle*

“…Numerical results show that the flow rate remains constant when the exit is far from the wall and increases exponentially when the exit moves close to the wall. [5] Shaking the hopper is another method frequently used to enhance the flow rate. [6,7] By an external vibration, the arches near the orifice that block the flow become unstable and are readily broken.…”