EOS of a material mixture in pressure equilibrium

A procedure is presented for calculating the equation of state (EOS) of a material mixture whose constituents are in pressure equilibrium but not necessarily in temperature equilibrium. A Newton-Raphson iteration is performed to determine the constituent partial volumes and energies that give equal partial pressures subject to the constraints that the total volume and energy of the mixture are specified. During each iteration, the changes in EOS quantities are chosen to be fixed (but arbitrary) linear combinations of their temperature-equilibrium and isentropic values, so those two extremes can be reproduced as special cases. The changes in the constituent partial volumes and energies are limited to prevent the Newton-Raphson iteration from diverging