A correlation of the isentropic exponents of real gases

In previous publications, three isentropic exponents, k_pv, k_Tv, k_pT, have been introduced, which when used in place of the classical isentropic exponent k = c_p/c_v in the ideal gas isentropic change equations, the latter can describe very accurately the isentropic change of real gases. The present work provides a general method for determining the values of k_pv, k_Tv, k_pT within the ranges of reduced pressure p_r = 0 to 10 and of reduced temperature T_r = 1 to 3.5, thus allowing the calculation of the isentropic flow of those real gases for which no detailed thermodynamic data are available. The accuracy obtained is limited only by the accuracy of the generalized Lee-Kesler equation of state, which is employed in the method developed.