TUBE SETTLER MODELING

A new tube settler model useful for tube design and performance evaluation is developed based on the assumption of uniformly distributed flow velocity at the tube entrance. As flow through the tube occurs, the velocity distribution in the tube changes from uniform flow to a fully developed parabolic velocity (laminar) profile at some distance along the tube. The varying velocity encountered by a settling particle results in variations in its settling path. A model is developed based on these effects and is verified in laboratory tests. Using the model, the effects of solids accumulation on the bottom of essentially horizontal tubes on particle settling is predicted. Laboratory tests indicate that the model predictions are accurate up to the point that 40% of the tube diameter is used for solids storage. © ASCE.