Study of versions of thermodynamic perturbation theory for simulation of the properties of binary mixtures of fluids in wide ranges of pressures and temperatures

The article considers the main provisions of three versions of perturbation theory: BH (D. Henderson and J.A. Barker), WCA (J.D. Weeks, D. Chandler, and H.C. Andersen), and KLRR (H.S. Kang, C.S. Lee, T. Ree, and F.H. Ree) used to calculate the thermodynamic properties of binary mixtures of dense gases in a wide range of pressures and temperatures. The interaction of molecules is described using the spherically symmetric pair potential exp-$6$. Verification was carried out by comparing experimental data on the compression of binary helium–hydrogen and ammonia–hydrogen mixtures, as well as on shock-wave compression of liquid $\rm N_2{,}~\rm O_2$ with the results of equilibrium thermodynamic calculations and Monte Carlo simulations. It is shown that for thermodynamic simulation of the properties of binary mixtures, the most accurate version of perturbation theory is the modernized KLRR-T theory.