Nonlinear transport effects in mass separation by effusion

TL;DR

This paper extends Onsager reciprocity to nonlinear ballistic transport in gaseous effusion, revealing significant effects on mass separation efficiency and showing that entropy efficiency can surpass linear predictions.

Contribution

It establishes generalized reciprocity relations for nonlinear response coefficients in effusion, based on the fluctuation theorem, and highlights their impact on mass separation processes.

Findings

Nonlinear response coefficients obey generalized reciprocity relations.

Nonlinear effects significantly enhance entropy efficiency in mass separation.

Entropy efficiency exceeds linear response predictions.

Abstract

Generalizations of Onsager reciprocity relations are established for the nonlinear response coefficients of ballistic transport in the effusion of gaseous mixtures. These generalizations, which have been established on the basis of the fluctuation theorem for the currents, are here considered for mass separation by effusion. In this kinetic process, the mean values of the currents depend nonlinearly on the affinities or thermodynamic forces controlling the nonequilibrium constraints. These nonlinear transport effects are shown to play an important role in the process of mass separation. In particular, the entropy efficiency turns out to be significantly larger than it would be the case if the currents were supposed to depend linearly on the affinities.