Hindered settling with an apparent particle diameter concept

- A settling velocity formula of sediment particle in sediment-fluid mixture is proposed.
- Richardson and Zaki equation is modified by a newly proposed exponent nH.
- An apparent diameter of sediment particle is proposed.
- A new expression of mass density of sediment-fluid mixture is suggested.

In this work a new expression has been developed to predict the settling velocity of a sediment particle which is dispersed in a sediment-fluid mixture during a turbulent flow. A concept of apparent particle diameter has been introduced and is defined by the diameter of the spherical volume in which the particle can move randomly after collision with other particles in suspension. The effect of suspension concentration is studied on the mass density of the sediment-fluid mixture. It has been shown that the settling velocity of sediment particle in a sediment-fluid mixture is a function of different characteristics of the sediment particle such as settling velocity in clear fluid, suspension concentration, relative mass density and Reynolds number. The model has shown good agreement when compared with previously published experimental data and it's prediction accuracy is superior than the other existing models.