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Stokes Law describes the settling velocity of small spherical particles in a viscous fluid. It is widely used in industrial processes to optimize sedimentation and clarification systems. Understanding this law helps in designing equipment that efficiently separates solids from liquids.
Fundamentals of Stokes Law
Stokes Law states that the settling velocity (v) of a particle is proportional to the square of its radius and the difference in density between the particle and fluid. The formula is:
v = (2/9) * (r² * g * (ρp – ρf)) / η
Where r is the particle radius, g is acceleration due to gravity, ρp and ρf are the densities of the particle and fluid, respectively, and η is the fluid’s viscosity.
Application in Sedimentation Tanks
In industrial settings, sedimentation tanks rely on the principles of Stokes Law to separate solids from liquids. The design involves calculating the required tank height and flow rate to ensure particles settle within a specific time frame.
Operators adjust parameters such as flow velocity and particle size to optimize the clarification process. Proper understanding of particle settling velocities ensures efficient removal of suspended solids.
Factors Affecting Sedimentation Efficiency
- Particle Size: Larger particles settle faster, improving clarification.
- Fluid Viscosity: Higher viscosity slows particle settling.
- Density Difference: Greater difference enhances settling velocity.
- Flow Rate: Excessive flow can carry particles out of the tank.