Kumar Equation of State

The Kumar equation of state (Kumar, 1986 Kumar et al., 1987) is a modification of the Panayiotou-Vera model that was developed to simplify the calculations for multicomponent mixtures. Since the Panayiotou-Vera equation is based on the lattice model with the quasichemical approach for the nonrandomness of the molecules in the mixture, the quasichemical expressions must be solved. For a binary system the quasichemical expressions reduce to one quadratic expression with one unknown, but the number of coupled 

The advantages of the Kumar equation of state are purely computational. The resulting expressions are approximations to the Panayiotou-Vera equation of state that will reduce to the proper forms for random conditions. Kumar et al. (1987) state that the expressions in Panayiotou and Vera (1982) differ because of errors in the Panayiotou and Vera work. The Vera and Panayiotou expressions have been shown to be correct with the methods described by High (Chapter 5, 1990). Thus, the discrepancies between the Kumar equation of state and the Panayiotou and Vera equation of state must occur in the approximations due to the Taylor series expansion. 

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