Equation number 3 from:
The International Association for the Properties of Water and Steam
Gaithersburg, Maryland, USA
September 2001
Supplementary Release on Backward Equations for Pressure as a
Function of Enthalpy and Entropy p(h,s) to the IAPWS Industrial
Formulation 1997 for the Thermodynamic Properties of Water and Steam
function p2a_hs extends Modelica.Icons.Function; input SI.SpecificEnthalpy h "Specific enthalpy"; input SI.SpecificEntropy s "Specific entropy"; output SI.Pressure p "Pressure"; end p2a_hs;