Thermodynamics, 5th Edition

Chapter 6

Irreversible Thermodynamics

6.0 Introductory Comments

We now study thermodynamics in the proper sense of the word. We consider irreversible processes that arise because one or more intensive variables in a system are rendered nonuniform. So long as variations in T, P, and ρ (temperature, pressure, and density) or other intensive quantities are “small” relative to their average values, one can still apply the machinery of equilibrium thermodynamics as shown below. In what follows the identification of conjugate forces and fluxes, the Onsager reciprocity conditions (ORC), and the rate of entropy production play a central role.

6.1 Generalities

Nonequilibrium phenomena necessarily involve states in which different portions of a given system ...