Calculations for Extended Thermodynamics of dense gases up to whatever order and with only some symmetries

TL;DR

This paper extends the thermodynamic calculations for dense gases using the 14 moments model, deriving closures at arbitrary order without additional symmetry constraints, revealing that non-symmetric parts only emerge at third order.

Contribution

It provides a general closure method for the 14 moments model at any order without imposing extra symmetry conditions, clarifying the order at which non-symmetric parts appear.

Findings

Non-symmetric parts appear only at third order with respect to equilibrium.

The constant associated with first-order non-symmetric parts must be zero.

The closure method applies to arbitrary order without supplementary symmetry constraints.

Abstract

The 14 moments model for dense gases, introduced in the last years by Ruggeri, Sugiyama and collaborators, is here considered. They have found the closure of the balance equations up to second order with respect to equilibrium; subsequently, Carrisi has found the closure up to whatever order with respect to equilibrium, but for a more constrained system where more symmetry conditions are imposed. Here the closure is obtained up to whatever order and without imposing the supplementary conditions. It comes out that the first non symmetric parts appear only at third order with respect to equilibrium, even if Ruggeri and Sugiyama found a non symmetric part proportional to an arbitrary constant also at first order with respect to equilibrium. Consequently, this constant must be zero, as Ruggeri, Sugiyama assumed in the applications and on an intuitive ground.