Constitutive Equations for Thermopolar Materials with Microscopic Gradient of Temperature

Thermodynamic quantities of state are defined under the nonequilibrium processes by the thermopolar theory. Constitutive equations for thermopolar materials are constructed on the basis of the results of the previous reports. As preliminary data, the arguments of the quasi-conservative part of the constitutive equations are restricted by the Clausius-Duhem inequality derived in the previous report. Moreover, the thermodynamic potentials are discussed; these are not only Helmholz's free energy, but also newly defined thermodynamic potential characterizing thermopolar materials. Then dissipative parts of the constitutive equations are restricted to satisfy the principle of maximal dissipation rate. Furthermore, the constitutive equations for thermopolar materials are constructed thermodynamically on the basis of the above discussion. Consequently, considering the physical interpretations of the linear constitutive equations, it is indicated that both the quasi-conservative internal force and the dissipative internal forces depend on the microscopic gradient of temperature.