The rising motion of grains in a vibrating pipe

Abstract

The rising motion of grains in a vibrating pipe is studied experimentally and by DEM (discrete element method) simulations. A pipe is partially inserted into a static granular layer. With the pipe initially filled with a certain height of grains, when the pipe is set into vertical vibrations, grains in the pipe will rise along the pipe and the motion will be finally stabilized at a certain height. The rising height and the speed of motion are strongly dependent on the vibration strength. By using a high speed camera and through DEM simulation, the trajectory of individual grains and the force acting on the grains in each vibration cycle can be obtained. A force-based mechanism for this rising motion is proposed. During vibrations of the pipe, the grains in the pipe are compacted and loosened alternately, and the force of the pipe and the grains varies periodically, thus leading to the rising motion of grains. A new possible way of continuously transporting grains is presented in this work.