振動粉体層に対する微粉体の通過特性

抄録

The percolation of fine particles through packed bed of coarse powder was studied in the vibrating state. CaCO₃, α-Al₂O₃, glass beads, nylon powder, graphite and potato starch were used as sample powders. The percolation curves seemed to consist of two parts. In the initial stage, the percolation weight increased rapidly. This is considered to show the process where fine particles tend to drain through every hole of the packing structure of coarse particles without mutual interactions between them. Then, in this region, the percolation rate increased as the particle size ratio of fine powder to coarse powder decreased. However, the percolation behaviors are dependent upon the kinds of materials and the properties of particle surface.
In the latter region where the increasing rate of percolation weight is very slow, it is considered that the movement of the fine particles through the packed bed is affected by the adhesion of fine particles to the surfaces of coarse powders. With combination of fine and coase powders, the percolation curves are measured in various amplitudes of vibration. There are critical points at which the percolation weight in the initial region decrease rapidly with the decreasing amplitude. It is considered that the kinetic energy of fine particles at this critical point corresponds to the adhesive force between the fine particles and the coarse particles. This technique is considered to be available for the measurement of interaction force between the particles of different materials.