Entropy balance equation for a dense gas

This work is concerned with the description of the time evolution for the entropy functional in a dense fluid out of equilibrium. We consider the fluid as a collection of N particles interacting via the superposition of pairwise additive short range intermolecular potentials. Such an interaction is assumed to be central and the particles do not have internal structure. To reach this goal we use the maximum entropy formalism in which the Gibbs entropy is maximized under the restrictions imposed by the normalization of the N-particle distribution function and the knowledge of the one and two-particle distribution functions. This procedure leads to an expression for the entropy functional in terms of such distribution functions. On the other hand, the evolution equations allow for the construction of a balance equation for the entropy functional in the system. An analysis of the entropy flux and entropy source is given for a particular expression in the Lagrange multipliers coming from the maximization procedure. Such an analysis shows the connection of the entropy production with the conversion rate of kinetic and potential energy between particles. Interesting conclusions about the temperature are reached in this case.