Chapter 5 - Energy Flow – Thermodynamics

Abstract

This chapter is concerned with the thermodynamics of systems not at equilibrium. Thermodynamics is the study of the flow of physical and chemical quantities (such as momentum, heat, fluid and chemical components) through or within a system driven by thermodynamic forces. These forces comprise gradients in deformation, the inverse of the temperature, hydraulic potential and chemical potential. Systems not at equilibrium are characterised by competition between thermodynamic forces that tend to drive the system away from equilibrium and thermodynamic flows that tend to return the system towards equilibrium. If the work done by the forces balances the dissipation from the flows the system is at a non-equilibrium stationary state. If there is no flow then the system is at equilibrium which is another stationary state a system can approach. Systems held away from equilibrium by the addition of mass and/or heat or by deformation are driven to one or more non-equilibrium stationary states that may or may not be stable. We develop the basic framework that enables the behaviour of deforming chemically reacting solids to be described in terms of microstructural evolution and entropy production.