A cubic equation of state based on a simplified hard-core model

The Redlich-Kwong (RK) equation of state introduced in 1949 has been considered. the most accurate two-constant-parameter cubic equation of state. The other cubic equations which are mo re accurate than the RK equation contain either three, or more, parameters and/or their parameters are temperature-dependent. A New two-constant-parameter cubic equation of state, Z(m) = (v + 0.62b(m))/(v - 0.47b(m)) - (Sigma Sigmax(i)x(j)a(ij))v/RT)/[T(1/2)v(v + 0.47 Sigmax(i)b(i))]; b(m) = (1/4)(3 Sigma (i)Sigma (j)x(i)x(j)b(ij) + Sigma (i)x(i)b(ii)); b(ij) = (b(ii)(1/3) + b(jj)(1/3))(3)/2; a(ij) = (1 - k(jj))(a(ii)a(jj))(1/2), a(ii) 1.46243RT(cii)(3/2) V-cii; b(ii) = 0.41274V(cii) is introduced using a simplified molecular theory of hard-sphere fluids for its repulsive term. This two-constant-parameter cubic equation of state appreciably increases the accuracy of thermodynamic property predictions and phase equilibria of pure fluids and fluid mixtures over the equations of this category.