Theoretical calculations of tortuosity in the sedimentation bed

Abstract

By the use of a spherical model granules having variously sized intergranular interactions, sedimentation layers were formed with spherical and nonspherical granules with different porosity, ε, and the rate for vertical and horizontal directions of this sedimentation layer, qz and qxy, were theoretically calculated. It was thereby found that the rate changed with porosity and that the sedimentation layer was anisotropic in vertical and horizontal directions, even if the granules were spherical. In nonspherical granules, the rate was apparently different from that of spherical granules and the rate changed according to porosity and the ratio of radius (γa) in the direction of rotary ellipsoid to that (γb) in vertical direction to γa, i.e., γb/γa, and the sedimentation layer was also found to have anisotropy in vertical and horizontal directions. When solvation layer is taken into consideration, the effect of solvation layer on rate was found to be greater, the lager the axial ratio.