Sedimentation potential of a concentrated spherical colloidal suspension

The sedimentation behavior of a concentrated suspension of charged spherical particles is investigated theoretically. The sedimentation potential is evaluated taking the effect of double layer polarization into account. A cell model is adopted to describe the present multientities system, and a pseudospectral numerical scheme is used to solve the governing electrokinetic equations, which comprise a Navior-Stokes equation for flow field and a Poisson equation for electric field. Several interesting phenomena, which are absent if double layer polarization is neglected, are observed. For example, the ratio (E*/U*), E*, and U* being, respectively, the scaled sedimentation potential and the scale velocity, has a minimum if the electrical potential is low, and has a maximum if it is high. (C) 1999 American Institute of Physics. [S0021-9606(99)50523-0].