Non-limited vibrational effect on shock-induced phase transitions of condensed fluid in hard-sphere model

Abstract

The essence of fluid phase transition is the jump of physical properties distinctly induced by shock waves in the hard-sphere model. Due to the strong impact of the wave, the internal freedoms of molecules are stimulated, releasing tremendous energy that commonly triggers the phase transition. Conversely, typical thermal and dynamic jumps can be described by the Rankine–Hugoniot conditions based on the Euler equation. In the theoretical simulation, the initial density and rotational freedoms of molecules are directly regarded as the primary factors to affect processes of phase transition. However, the influence of vibrational freedom in molecules has not been discussed yet. As the increasing temperature can gradually excite the affection of vibrational freedom, it is unwise to assume that the temperature element is constant in the theory. What would be a suitable model that accurately reflects the relationship between temperature and affection from vibrational freedom? The non-limited model has been courageously attempted with the temperature range from T0 to 6T0 (T0 is unperturbed temperature). We have found that the vibrational freedom can have a great effect on properties during phase transition processes.