We characterize the dynamics of a zβz electrolyte embedded in a
varying-section channel. In the linear response regime, by means of suitable
approximations, we derive the Onsager matrix associated to externally enforced
gradients in electrostatic potential, chemical potential, and pressure, for
both dielectric and conducting channel walls. We show here that the linear
transport coefficients are particularly sensitive to the geometry and the
conductive properties of the channel walls when the Debye length is comparable
to the channel width. In this regime, we found that one pair of off-diagonal
Onsager matrix elements increases with the corrugation of the channel
transport, in contrast to all other elements which are either unaffected by or
decrease with increasing corrugation. Our results have a possible impact on the
design of blue-energy devices as well as on the understanding of biological ion
channels through membrane