Fluid/Particle Separation Journal
Separation (Technology) -- Mathematical models, Density currents, Sewage clarifiers, Hydrodynamics -- Computer simulation
Design of sedimentation tanks for solid-liquid separation is often dependent on assuming ideal flow conditions. But the geometry of the tank and density currents as a result of temperature and suspended solids influences the fluid mechanics of the tank and can result in significant deviations from ideal flow.
A two-dimensional radial flow model was proposed which incorporated the effect of density currents resulting from temperature and suspended solids differentials within the tank. The numerical model predicted the steady-state, layer-averaged radial flow and layer depth.
The model solution and field data showed that the momentum and suspended solids of the inflow caused a density current that moved along the clarifier bottom. In the winter, this density current rose as a result of warm inflow water after the initial momentum had decreased and the suspended solids had settled.
Wells, Scott A. and LaLiberte, David M., "Modeling Density Currents in Circular Clarifiers" (1998). Civil and Environmental Engineering Faculty Publications and Presentations. 128.