Constitutive Equations for Internal Variables Thermodynamics of Suspensions

A description of mixtures, including matter diffusion and suspensions, is analyzed from a thermodynamic viewpoint with internal variables. In order to consider dissipative effects due to thermo-diffusion we introduce a set of N independent scalar internal variables, which we denote by. A. The behavior of the mixture is therefore described by a state space W including the classical variables mass density, mass concentration, temperature, and internal variables together with their first and second gradients satisfying evolution equations. General thermodynamic restrictions and residual dissipation inequalities are obtained by the Clausius-Duhem inequality