Settling ratio, free hindered

When a particle is at a sufficient distance from the walls of the container and from other particles so that its fall is not affected by them, the process is called free settling. Interference is less than 1% if the ratio of the particle diameter to the container diameter is less than T.200 or if the particle concentration is less than 0.2 vol % in the solution. When the particles are crowded, they settle at a lower rate and the process is called hindered settling. The separation of a dilute slurry or suspension by gravity settling into a clear fluid and a slurry of higher solids content is called sedimentation. 

Impeller diameter (ft, m) diffusivity (ft /h, mVs) mass-mean diameter (ft, m) mean particle diameter of the ith size (ft, m) particle size or diameter (ft, or m) gravitational constant (32.17 ft/sec or 9.81 m/sec ) diffusional mass transfer coefficient rate of diffusional mass transfer impeller speed (rps) number of particles in the ith size class impeller speed for just suspended state of particles (rps) impeller power (hp, W) vessel diameter (ft, m) particle-free settling velocity (ft/s, or m/s) particle-hindered settling velocity (ft/s, or m/s) mass ratio of suspended solids to liquid time 100 (kg solid/kg liquid) X100 liquid depth in vessel (ft, m)... 

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