The H2 Gas Diffusion Layer and O2 Gas Diffusion Layer nodes specify domains where both an Electronic Conducting Phase and a Gas Phase node are active.

The effective electronic conductivity, Effective electrical conductivity, σs (SI unit: S/m) parameter will define how the electric current in the corresponding Electronic Conducting Phase domain depends on the gradient of the potential.

This section will only be visible if the Include gas phase diffusion check box or the Use Darcy’s law for momentum transport check box has been selected in the corresponding Gas Mixture section on the interface top node.

If the Include gas phase diffusion check box has been selected, the gas diffusivity defined in the Gas Phase node will be multiplied by a correction factor to compensate for the effect of the Gas pore volume fraction being less than 1. This can be done by either using a Bruggeman, Tortuosity or a User defined correlation.

If the Use Darcy’s law for momentum transport check box has been selected, the Gas permeability is defined in this node.