Settling Velocity

Definition

The steady downward speed at which a particle settles in still fluid, set by its size and density relative to water.

A 100 micron sand particle (density about 2,650 kg per cubic meter) settles at roughly 8 mm per second, while a 10 micron silt particle settles about 100 times slower at 0.08 mm per second. At typical cooling tower piping velocities of 3 to 6 feet per second, fine silt has no chance to settle and stays suspended indefinitely. Comparing settling velocity to flow velocity tells you which removal mechanism will work.

Related concepts

Particle Size Distribution · Stokes’ Law · Settling

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Part of The Blueprint of Water · 📏 measurement