Intensive regimes and violation of the local equilibrium condition in transfer equations

Abstract

The structure of the complete system of mass, momentum, and energy transfer equations has been formulated in terms of microscopic fluid dynamics for highly nonequilibrium conditions, when there is no local equilibrium condition, contrary to a conventional assumption of nonequilibrium thermodynamics. Mass, momentum, and energy transfer has been described at the atomic/molecular level using nonequilibrium discrete unary and binary distribution functions (lattice gas model) with allowance made for the interparticle potential interactions of molecules in the system. The complete system of equations includes five modified fluid dynamic equations and new equations describing mean-square fluctuations of all dynamic variables (density, velocity components, and temperature). The transfer equations constructed here refer to inhomogeneous systems with arbitrary density, specifically to a liquid and a gas (vapor) and their interface. Conditions for passing to the conventional transfer equations and the relation of the equations set up in this study to the existing methods of taking into account velocity pulsation are discussed.