INTERPOLATION EQUATION OF STATE FOR WATER AND VAPOUR

L.F. Gudarenko, V.A. Zherebtsov
VANT. Ser.: Mat. Mod. Fiz. Proc 1994. Вып.3. С. 57-64.

      The paper seeks to construct a tabulated-analytical equation of state on the basis of the tables with thermodynamic data for water and water vapour. Table data approximation is performed with polynomial spline functions. The equation of state allows to compute thermodynamic functions together with their derivatives with respect to any of the following three pairs of variables: density - temperature, density - energy, density - pressure. The domain described by the equation of state is the following: density — 0 < ρ < 1 g/cm³; pressure - 0 < P < 0,1 GPa; specific energy - 0 < E <3,7kJ/g; temperature - 0 < T < 800ºC. The equation is intended to compute a compressible medium flow when choosing structural elements of power systems and to substantiate their carrying capability.