CALCULATION OF THE NONEQUILIBRIUM SYSTEMS CONSISTING OF AN AGGREGATE OF LOCALLY-EQUILIBRIUM SUBSYSTEMS

The basis of SLT is the postulate of nonequilibrium, according to which there is an objective property of matter – “nonequilibrium”, which characterizes the uneven distribution of matter and motion in space. A new formulation of the SLT is given in relation to the set of locally equilibrium subsystems that make up the nonequilibrium system: when real (irreversible) processes occur, the nonequilibrium of the isolated system (IS) decreases, and in reversible processes the nonequilibrium in the system of locally equilibrium subsystems does not change (the increment of one kind of nonequilibrium completely compensated by a decrease in the disequilibrium of some other kind). The maximum work that can be done when the nonequilibrium system goes into equilibrium is considered as a quantitative characteristic of the nonequilibrium system. The article provides a calculated confirmation of the theoretical provisions of the concept of nonequilibrium and its mathematical apparatus by examples of determining the loss of IS disequilibrium during operation of a heat engine performing an irreversible cycle and the nonequilibrium state of an adiabatic system (AS). Schemes of an IS consisting of a hot body, the environment, and a working fluid performing a temperature-imperfect Carnot cycle are given, as well as an AS consisting of the environment and a working fluid, upon expansion of which work is given to an external work receiver. It is shown that the external work of the adiabatic system should be determined not by the decrease in the thermodynamic potential of the working fluid, as is generally accepted, but by the decrease in the potential of all AS bodies (the working fluid and the environment). As a result, analytical expressions are obtained for the practical calculation of nonequilibrium and its reduction during real processes in systems consisting of an aggregate of locally-equilibrium subsystems, which is new in thermodynamics.