Analytical equation of state for liquid and gaseous nitrogen

Based on the previously developed method for constructing the equation of state (EOS) for liquid and vapor, the thermodynamically consistent analytical equation of state for liquid and gaseous nitrogen (in the molecular phase) is obtained. While constructing the equation of state, the Mie – Gruneisen form was used as a sum of potential and thermal components for pressure and internal energy. The potential components are described by a potential of the Born–Meyer type. For the thermal components, a simplifying approximation is adopted that follows from the condition for the constant average heat capacity and the dependence of Gruneisen function on the volume. When deriving the equation of state for nitrogen vapor and liquid phases, the tables calculated from equations approximating experimental data on isothermal compressibility, adiabatic speed of sound (including the critical region and phase equilibrium line) were used. The obtained equation of state for nitrogen can be useful in studying the phenomena associated with the processes of nitrogen evaporation and condensation in multiphase flows. This modeling takes into account the interfacial heat and mass transfer under conditions of low pressures and cryogenic temperatures.