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Velocity Gradient Optimization in a Perforated Tray-Type Flocculator using OpenFOAM: CFD as a Tool in Water Treatment
Author(s): Pâmela Melo, Evelise Freire, Jonas Laerte Ansoni, Luiz Oliveira, Camila Franco
Keywords: Water Treatment Plant, turbulence, floc rupture, orifices, hydraulics.
Analyzing the efficiency of flocculators through computational fluid dynamics simulation can be essential to the optimization of Water Treatment Plants. Therefore, the aim of this study is to simulate the velocity field in a perforated tray-type flocculator, and quantify locally velocity gradient (G) through Computational Fluid Dynamics (CFD) methodology. Thus, simulations occurred at flocculator’s current operational flow rate (7 L s-1), and at full capacity (9 L s-1). An alternative modification was tested by increasing the perforations in flocculator’s trays. As result, dead zones were observed at the edges of the tank for all simulations, which facilitates short circuit occurrences. This is an indicator of reductions in water treatment efficiency. As the flow rate increases, the maximum G at the orifices increases considerably (75 to 110 s-1), causing a risk for floc rupture. However, by changing the perforations from 22 to 33, it was possible for the flocculator to operate at higher flow rates without increasing the velocity gradient, also reducing dead zones.

Journal of Applied Fluid Mechanics

The Journal of Applied Fluid Mechanics (JAFM) is an international, peer-reviewed journal which covers a wide range of theoretical, numerical and experimental aspects in fluid mechanics. The emphasis is on the applications in different engineering fields rather than on pure mathematical or physical aspects in fluid mechanics. Although many high quality journals pertaining to different aspects of fluid mechanics presently exist, research in the field is rapidly escalating.