円筒容器における球形粒子の低速沈降堆積電算機シミュレーション: Tory充てんプログラムの改良

抄録

Tory's Computer simulation of the slow settling of spherical particles into a randomly packed bed is modified: After removing the periodical boundary of the wall and the randomly packed bed at the bottom, a new boundary condition of a cylindrical container is introduced. In order to identify the position of the particles in the container, the coordinate of cubical lattices of side 1.0 sphere diameters is devised and the particle numbers are stored in the corresponding three-dimensional array of the computer memory. This saves considerable amount of the necessary memory and the computer program becomes simple, comparing with Tory's method where small lattices of side 0.5×1.15 sphere diameters are used. The average volume fractions of the particles without the wall effect are 0.582 for uniform feeding of the particles over the cross-section of the container and 0.612 for the particle feeding from the center. In the latter, the bottom floor of the container affects the particle arrangement as far as 13 particle layers into the interior. For the other cases, however, the wall effects are on two particle layers only. Although the packing structures obtained from the computer simulation cannot be actual, experimental results, the data may be able to play important roles in the theoretical analysis.