Complete equation of state for shocked liquid nitrogen: Analytical developments

Area of Science:

• Thermodynamics
• Materials Science
• Chemical Physics

Background:

• Extensive research exists on liquid nitrogen's thermodynamic response, driven by interest in shocked molecular nitrogen dissociation.
• Prior equation of state (EOS) models for shocked liquid nitrogen primarily relied on atomistic calculations using intermolecular pair potentials.

Purpose of the Study:

• To develop new analytical models for liquid nitrogen's equation of state (EOS) suitable for continuum calculations.
• To extrapolate existing low-pressure reference data to high pressures and temperatures relevant to shock compression.

Main Methods:

• Incorporated analytical models into EOS development for liquid nitrogen.
• Utilized available Hugoniot data to extend a reference EOS for molecular nitrogen to high P-T conditions.
• Performed continuum calculations for single, double, and multiple shock compressions.

Main Results:

• The developed EOS provides accurate predictions for pressures and temperatures across a wide P-T range for shocked liquid nitrogen.
• Calculations show good agreement with experimental data for single, double, and multiple shock compressions.
• This study presents the first comparison of EOS developments with recent multiple shock compression measurements.

Conclusions:

• The new analytical EOS for liquid nitrogen accurately models its shock compression response.
• These EOS developments are general and applicable to other liquids with available low-pressure reference data.
• The findings advance the understanding of nitrogen under extreme conditions and provide a valuable tool for shock physics research.