background image
INFLUENCE OF THE METAL PAD CURRENT DENSITY FIELD
ON THE MHD CELL STABILITY

In order to illustrate the impact of the change of intensity of the horizontal current
in the metal pad on the cell stability, the same three cases will be analyzed again with
MHD-Valdis but this time using the busbar design inspired from the Pechiney 1987
patent [9] (see Figure 13). That busbar design is producing a more stable cell than the
one available in our 3D ANSYSŪ based 500 kA demonstration model, so it is better
suited for this comparative cell stability study.
Figure 13: MHD-Valdis electric network model mesh with compensation loop

A very similar stability analysis study of this 500 kA demonstration cell design
with that busbar configuration has already been presented in [10]. The only difference
being that the metal level in the previous study was setup to 25 cm while it is set to 20
cm in the present case. The ledge toe thickness is set to 4 cm, very close to the anode
shadow, as it was in the previous study.

Figure 14 presents the obtained initial metal pad current density field. The
intensity of the cell longitudinal component (Jx) is slightly different from the one
presented in Figure 6 because the busbar network is better balanced in the present case.