to help locate the busbars around the cell in a way that leads to the

generation of a magnetic field inside the cell that itself leads to a

stable cell operation.

current density in the metal pad is also extremely important and can

only be achieved with a correct busbar network sizing.

of MHD-Valdis to help design a well balanced busbar network.

uniform current pick up in all the collector bars of a modern side by

side high amperage aluminum electrolysis cell, while known to be

critical to the cell MHD stability, is not often discussed in the

literature.

computer code called respectively NEWBUS and BUSCAL

designed specifically to do such a task. Both use a simple 1D line

busbar network representation, a temperature dependent electrical

resistivity and solve for the resulting non-linear problem by

computing the voltage and temperature equations iteratively and

alternately until convergence is reached. These days, such an in-

house solver can be setup fairly rapidly in an Excel spreadsheet

(see figure 1).

and the different currents in the busbar network are then transferred

to the metal pad current density solver and the metal pad magnetic

field solver in preparation to run the MHD wave stability solver.

order to very accurately compute the metal pad current density field

considering both the converged steady-state ledge profile and the

busbar design. Of course, once developed, the 3D busbar model

can also be solved stand-alone.

and rod implemented in an Excel spreadsheet.

a simplified 1D line network busbar representation and use that

tool to perform busbar sizing optimization and, on the other hand,

it is possible to develop an ANSYS

5 and 10] which is a commercially available, fully non-linear MHD

cell stability solver. The fact that it is fully non-linear, means that it

is solving among other variables the busbar network current

distribution at each time step. It is doing so using a versatile 1D

line network busbar generator and solver called BUSNET also

available to carry out busbar sizing optimization studies.

most efficient tool to carry out busbar sizing optimization studies,

but before proceeding with the comparison exercise, it is important

to take a step back and first review the background theory of the

equations that need to be solved.