Sammendrag
A simulator for coupled current distribution and convection in
electrolysis cells has been developed. The simulator solves the
electric and temperature fields in the electrolyte, electrodes and
surrounding solids, as well as the rate of anodic gas evolution and
the resulting convection in the electrolyte. The simulator is based
on the computational fluid dynamics software Fluent 4.5, to which
we have added a solver for the electric field including
electrochemical overvoltage. The surface potential model is based
on an iterative flux method. Furthermore, the amount of gas
released from the anode is a function of the local current density.
The resulting gas induced convection depends on gas mass flow
and bubble size. The local electric conductivity of the electrolyte is
a function of the local gas fraction. Calculations have been
performed for various cell geometries with both horizontal and
vertical electrodes. Effects of bubble size and cell geometry have
been studied. The physical parameters were chosen to match those
encountered in aluminium electrolysis, but the simulator is general
and can be applied to all kinds of electrolysis cells. Additional
calculations of side ledge heat transfer in Søderberg- and prebakecells
are presented and compared with measurements.
electrolysis cells has been developed. The simulator solves the
electric and temperature fields in the electrolyte, electrodes and
surrounding solids, as well as the rate of anodic gas evolution and
the resulting convection in the electrolyte. The simulator is based
on the computational fluid dynamics software Fluent 4.5, to which
we have added a solver for the electric field including
electrochemical overvoltage. The surface potential model is based
on an iterative flux method. Furthermore, the amount of gas
released from the anode is a function of the local current density.
The resulting gas induced convection depends on gas mass flow
and bubble size. The local electric conductivity of the electrolyte is
a function of the local gas fraction. Calculations have been
performed for various cell geometries with both horizontal and
vertical electrodes. Effects of bubble size and cell geometry have
been studied. The physical parameters were chosen to match those
encountered in aluminium electrolysis, but the simulator is general
and can be applied to all kinds of electrolysis cells. Additional
calculations of side ledge heat transfer in Søderberg- and prebakecells
are presented and compared with measurements.