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, q_z and q_xy, 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 (γ_a) in the direction of rotary ellipsoid to that (γ_b) in vertical direction to γ_a, i.e., γ_b/γ_a, 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.