Effects of vibration parameters and pipe insertion depth on the motion of particles induced by vertical vibration

Granular particles can be induced to move against gravity upwards through a pipe or tube that is partially inserted under the powder free surface while subject to vertical vibration. This offers a new approach for transporting bulk material. In this paper, the effects of both vibration parameters and insertion depth of a pipe on particle motion are experimentally studied. A minimum vibration amplitude (A) and frequency (f) are necessary for particle motion to occur. There is a monotonic increase of the final rise height of the powder (h_eq) with increasing amplitude A. However, h_eq exhibits a non-monotonic dependence on frequency, f. There is an optimum frequency at which particles climb highest, and any further increase of frequency leads to a diminishment of this upwards motion. A phase diagram of particle movement is presented which shows that different zones of motion exist. This unique finding suggests that the mechanism of particle movement is caused by the creation and filling of voids under the tube. Particles cannot move upwards when the pipe insertion depth, h_in is <1.5 mm irrespective of how strong the supplied vibration is. In general, increasing h_in can improve climbing, but this effect falls with increasing levels of insertion depth until a saturation level is reached. PACS number: 45.70.MG