粉粒体の凝集性(第3報)粒子形態の影響

Abstract

Influence of partic1e shape on cohesiveness of partic1es was studied. Experiments were made using the cylindrical particles such as vermicelli and copper wire having different diameter and length. The apparatus and procedures reported in the previous paper were used for cohesion measurement. The samples used were considered to have no diffence in their size and shape, and to have a geometrical shape, and seem to be convenient for determination of the shape factor (ψ). For simplification ; the ratio of dl to do was used as a shape factor, where dl is the diameter of the sphere inscribed with the particle and do is that of the one circumscribed with the particle. The effects of particle diameter (φ), length (l), and shape factor (ψ) on cohesive force (fe), and the apparent cohesiveness (αe) were shown experimentally. The relationship between fe and l gave almost a straight line, but fe and φ did not. This difference may be attributed to the difference in particle weight and the degree of leaning between particles which was represented as leaning efficiency (P) previously. The αe decreases with increase in particle diameter, and increases with particle length. It was found that the relation between αe and ψ can be given by αe=A lom ψ+B, where A and B are constants. This relation is recognized in the case of particles of other shape such as lactose granules with different size and shape. The inherent values of A with each sample were observed but the physical meaning of A is still obscure.