Particles in Newtonian fluid

Fig. 11.19 Viscosity of suspensions of spherical particles in Newtonian fluids, (a) Curve constructed by Bigg. [Reprinted by permission from D. M. Bigg, Rheological Behavior of Highly Filled Polymer Melts, Polym. Eng. Sci, 23, 206 (1983).] (b) Curves presented by Thomas (79).

Correlations for the free settling velocity have been derived for spherical particles. In Newtonian fluids, the free settling velocity, Vt, is calculated by the expression (Perry and Green, 1984). 

For such ideal systems as suspensions of spheres of equal diameter, many equations, either theoretical or empirical have been proposed for the relative viscosity as a function of the filler volume fraction. Such a subject is obviously of tremendous importance in many fields. A thorough discussion of suspensions of rigid particles in Newtonian fluids was made by Jeffrey and Acrivos and some models available up to 1985 were discussed in detail by Metzner.59 We will consider below only the most referred equations that explicitly consider the maximum packing fraction. One of the oldest proposal was likely made by Filers in order to model the behavior of highly viscous suspensions, i.e. ... 

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