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The real life flocculation tank designed by Aguaclara involved a 180 deg turn over few dozens baffles. For validating result and modeling purpose, a simple 180 deg turn over two baffles was modeled. The first step was to set up the geometry of the of the simple flocculator. For future comparison with the experimental data, the design parameters for the pilot plant test flocculator was modified and used.
Figure 1: Geometry of flocculatorFlocculator
The design parameters used are:
Height: 1m
Clearance: 0.15m
Baffle width: 0.1m
Velocity inlet: 0.1m/s
With the geometry, we the mesh for the model can then be set up the mesh for our model.
Figure 2: Meshing Parameters (Click on the figure to see the original size)
Figure 2 shows the meshing parameters that were used. The boundary layers was first establish at all the wall surfaces. The boundary layer was set up such that the solution obtain in gambit would provide result of y+ of less than 5. After that, the mesh edges were set up such that they will provide higher mesh resolution near the turn and lower resolution far from the turn. With the initial meshing conditions set up, all the faces were then meshed.
Figure 23: Mesh of the Flocculation Tank of the Model (Click on figure for original size)
Figure 3 shows the overall mesh of the flocculator model. As can be seen, the mesh is fine near the turn and at the wall. The final step at this point was to set up the boundary conditions of the system.
Figure 34: Boundary condition for modelingConditions
Figure 3 4 shows the boundary condition that was used for modeling. For a flocculator, there is an in flow and out flow of the fluids. Since we know the inlet velocity inlet was known from the experimental data, the inlet was set to the Velocity Inlet type boundary condition. And since we know the outlet pressure is known, the outlet is The outlet was set to Pressure Outlet boundary condition type, the atmospheric pressure.
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