Use the Sacrificial Edge Anode node to model rod-shaped dissolving metal electrodes in corrosion protection applications. The node is defined on an edge in a 3D geometry, and the electrochemical reactions are defined on a virtual tube in the geometry, located at a given radius around the edge. A Sacrificial Edge Anode can only be applied to edges within, or adjacent to, Electrolyte domains. The node is only available when a Secondary Current distribution type has been chosen on the top node.

As the metal electrode dissolves, the edge radius decreases. In time-dependent simulations, the node solves for a capacity (SI unit: C/m) degree of freedom to keep track of the total amount of passed charge along the edge. The edge radius is defined so that it equals Initial radius (m) at the Initial capacity (SI unit: C/m), reaching the Terminal radius (m) when the capacity reaches zero.

The actual dissolution rate is defined by the Electrode Reaction subnodes. By enabling Set current density to zero at depletion, all current densities are set to zero when the capacity goes to zero, using a smoothed step function. The Size of transition zone value sets the relative capacity for which the smoothing starts close to depletion.

Enable Add tangential diffusion to improve convergence by smoothing out local capacity gradients along the edges.

The potential in the electronic phase is used by the Electrode Reaction subnodes in the kinetics expressions. It can be defined by a Fixed electric potential, a Floating potential or an External short electric potential. The floating potential allows to specify the total current flowing through all edges selected by the node. The External short allows to connect two electrodes over an external connector with a given bulk resistance.

See the Electrode Surface node.

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