Modeling in Nonequilibrium Thermodynamics

Abstract

Until now, we have dealt with applications from either classical mechanics or electrical circuits exclusively. In this chapter, we shall discuss nonequilibrium state thermodynamics. Most engineering students consider thermodynamics a rather difficult topic. The reason for this seeming difficulty lies in the fact that basically all available treatises of thermodynamics have been written by physicists rather than by engineers. Physicists are, by education, phenomenologically rather than systemically oriented. They do not wish to change the world, only to understand it. Therefore, their approach to dealing with problems is quite different from ours. Rather than looking at a system as a whole and trying to analyze the couplings of its subsystems (as we engineers do), they always try to single out individual phenomena and discuss those in isolation. As a consequence, most physics texts present the topic through a collection of various formulae, which are all individually correct and meaningful but hard to relate to each other. It is the aim of this chapter to bridge the gap between those individually well—known equations that govern the behavior of nonequilibrium state thermodynamic systems. According to Jean Thoma, another reason why most thermodynamics textbooks are obscure is the fact that they avoid to work with entropy flow as a physical variable.