The Dorr-Oliver Flotation cell

1
The Dorr-Oliver Flotation cell
Six blade impeller
Stator with 4 large blades and 12 small
2
The three studied Configurations for Re35000
y
x or r
1cm
3cm
1cm with stator
3
Normalized velocity magnitude contours
4
Normalized radial velocity contours
5
Normalized TKE contours
6
Normalized Dissipation rate contours
7
Normalized Z-vorticity
8
Streamlines along a horizontal plane of the
impeller at
9
Y-vorticity along a horizontal plane of the
impeller at
10
TKE along a horizontal plane of the impeller at
11
Dissipation rate along a horizontal plane of the
impeller at
12
Streamlines along a horizontal plane of the
impeller at
In the first two cases some of the flow is
returning back from the two recirculation regions
next to the impeller while some of it is still
going out
In the case with the stator most of the flow is
returning back from the huge recirculation
region while some of it inside the stator still
tries to pass through.
13
Y-vorticity along a horizontal plane of the
impeller at
14
TKE along a horizontal plane of the impeller at
15
Dissipation rate along a horizontal plane of the
impeller at
16
Streamlines along a horizontal plane of the
impeller at
17
Y-vorticity along a horizontal plane of the
impeller at
18
TKE along a horizontal plane of the impeller at
19
Dissipation rate along a horizontal plane of the
impeller at
20
Conclusions

• The Fluent code can predict in many features of
  the flow in a flotation cell, but so far,
  single-phase flow was considered.
• The turbulent kinetic energy and dissipation have
  the highest values in the immediate neighborhood
  of the impeller
• Stators generate recirculation patterns that lead
  the flow upward in the center of the tank, and
  thus promote flotation.
• Stators generate significant increases in
  turbulent dissipation and thus could promote the
  collision of bubbles and particles.

21
Future Work

• Experimental predictions for the Dorr-Oliver
  Flotation cell
• Comparisons of the studied cases with the
  experiments
• More Re numbers and clearances for the
  Dorr-Oliver Cell
• Higher Re numbers for both Tanks (100000-300000)
• Unsteady calculations
• Extension to two-phase or three phase flows