...
The simplification of a single baffle turn eliminated important behavior within the flocculator. Multiple baffles enabled us to see the interaction between different baffles.
Figure 1: Velocity Magnitude for three turns case
Figure 1 shows the flocculation tank with three baffles turning. As can be seen, the fast moving fluid after first turning propagated to the second turning.
Intuition will tell us that the velocity at the second turning will further increase because of the faster incoming flow at second bend. Surprisingly enough, at second turn, the outer edge velocity is lower compared to the first turn.
...
Figure 2: Turbulence Dissipate Rate for three turns
...
One explanation of such phenomena is that the faster moving fluid can't turn fast enough and impinges on the wall. Upon investigating contour of turbulence dissipation rate, illustrated in figure 2, we see that there is a very high region of energy dissipation rate right after the second turn. The high energy dissipation rate region explains why we have a smaller velocity.
...
The five baffle turns enables high dissipation regions to interact. The geometry to investigate is presented below in the automization of the mesh in GAMBIT. Below is the case where baffle spacing is fixed at .1, and the flocculator height is fixed at .1. This results in a regions of high velocity magnitude, "undeveloped" energy dissipation regions, and a uniform energy dissipation value.
.
Figure
...
Figure 3: Velocity and Turbulence Dissipate Rate for five turns
...
This problem is rich in geometric variables, and our investigation found that a larger height baffles is more optimal. Below is Figure 4 shows the velocity and energy dissipation plots for flocculation height of .3:
...
Figure 4: Velocity and Turbulence Dissipate Rate for fh = 0.3
...
Note that the overall epsilon value range (max at .01) is lower than the plot above which has a max of (.05), but has comparatively more uniform distribution for baffles turns 3 and 4.