The name is absent

Chapter 2

2.3.3. Sedimentation and creaming

Sedimentation or creaming takes place when the two liquids exhibit different
densities due to gravity. Stokes equation can describe the terminal sedimentation
velocity of spheres in Newtonian fluids.

^v∙^{= [2}-⁹¹

18τ∕_c

Here v_s is the terminal sedimentation velocity, ∆p is the density difference of
dispersed and continuous phase, d is the diameter of droplet, ηc is the viscosity of
continuous phase, g is the acceleration either due to gravity (g = 9.81 m∕s²) or to
centrifugation (g = Lω², with L being the effective radius of the centrifuge and ω
the angular velocity). If ∆p > O, emulsions sediment; otherwise, the process is
referred to as creaming. Sedimentation applies to most W/0 emulsions and solid
dispersions; creaming applies to most 0/W emulsions and bubbles dispersed in
liquids.

Eq. [2.9] is only satisfied for very dilute dispersions. If the volume fraction of
the dispersed phase φ is significant (say φ > 0.01), so-called hindered
sedimentation takes place. In general, the effect of φ is to reduce the
sedimentation rate due to hydrodynamic interactions among droplets. The
expression is as follows ^[16]:

16

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