粒度分布をもつ球形粒子群のランダム充てんにおける空隙率と粒子接触数
1973 年 22 巻 238 号 p. 658-662
詳細
1973 年 22 巻 238 号 p. 658-662
The relation between contact number and porosity in randomly packed beds of mixtures of various-sized spheres was investigated. The materials used were polystyrene spheres of 1-6mm in diameter. The spheres were separated by sieving into five size fractions. Three samples having various size distributions were prepared by remixing the appropriate spheres of different size fractions.
The packed beds were prepared by various methods of packing. The porosity values were ca. 0.64 for loose packing and ca. 0.37 for dense packing. Red ink was poured into the packed bed, filled it up and then drained. The ink was held by capillary force at each contact point after draining. After drying, the marked spheres were separated by sieving into original size fractions, and the distribution of contact numbers was obtained by counting the number of ink marks on each sphere in the same fraction. The contact number in each fraction showed normal distribution, and it increased with increasing particle size and with decreasing porosity. When the porosity became above 0.45, the relation between the mean contact number and porosity coincided with the result obtained by Ridgway and Tarbuck.
