The influence of diffusion on the determination of particle-size distribution by gravitational and centrifugal sedimentation

Abstract

In previous papers expressions for the influence of diffusion on gravitational sedimentation were calculated for products with characteristics [C(k)]ⁿ= ak for n=½, 1 and 2, and a = 5, and the results were, to a certain extent, generalised.

In the present paper the expressions for the arbitrary distributions are extended to cover all constant fields, and they may also be applied with sufficient accuracy to centrifugal sedimentation when the average acceleration in the sedimentation vessel is the same as the acceleration in the constant field.

Further, the expressions for heterodisperse products of arbitrary distributions are extended to cover very fine products and products for which the difference between the density of the particles and that of the suspending medium approaches zero.

Finally, the influence of diffusion by the examination of monodisperse products is calculated, and agreement is shown with the author's earlier papers dealing with these problems.