Thermal vibration phenomenon of single phase lagging heat conduction and its thermodynamic basis

In the present work it is shown that the single phase lagging heat conduction not only avoids the infinite heat propagation speed assumed by the conventional Fourier law, but also complies with Galilean principle of relativity. Therefore it is more advantageous than the Cattaneo-Vernotte model. Based on the single-phase-lagging heat conduction model, the condition for the occurrence of thermal vibration of heat conduction is established. In order to resolve the contradiction that the thermal vibration violates the second law of thermodynamics, the extended irreversible thermodynamics is improved and a generalized entropy definition is introduced. In the framework of the newly-developed extended irreversible thermodynamics the thermal vibration phenomena are consistent with the second law of thermodynamics.