Current Density
The Current Density node provides a boundary condition for the electric field which makes it possible to set the total current density at a boundary. The condition is defined as:
(3-109)
where n denotes the normal vector to the boundary and i0 is the inward current density.
It is common to combine this boundary condition with concentration conditions for the species. Such a combination is useful in cases where the flow in an electrochemical cell is vigorous and in cases where the whole cell is not treated in a model, most often when the opposite electrode is a far away. Half-cell investigations are very applicable for this type of condition.
Inward Current Density
Specify the current density i0 (SI unit: A/m2). Use a positive value for an inward current flow.