Thermodynamic Properties of Ordinary Water Substance for Industrial Use

in region 2 of IAPWS-IF97:

Backward Equations: p(h, s)

Developed by Russian National Committee (RNC) of

International Association for the Properties of Water and Steam (IAPWS).

This calculation page is based on the

"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" [1]

provided by IAPWS.

Detailed information about used equations, constants, range of validity etc is presented in PDF version of IAPWS

Authors (and responsible persons):

Input parameters

Formulation reference values

Dimensionless input parameters

Main backward equations

The pressure in subregion 2a is represented by the equation

Eq. (3) in [1]

Extracting data to vectors:

The dimensionless pressure in subregion 2a

Eq. (3) in [1]

The pressure in subregion 2a

The pressure in subregion 2b is represented by the equation

Eq. (4) in [1]

Extracting data to vectors:

The dimensionless pressure in subregion 2b

Eq. (4) in [1]

The pressure in subregion 2b

The pressure in subregion 2c is represented by the equation

Eq. (5) in [1]

Extracting data to vectors:

The dimensionless pressure in subregion 2c

Eq. (5) in [1]

The pressure in subregion 2c

Determining the subregion

The boundary between subregions 2a and 2b

Enthalpy for given entropy on the boundary line of subregions 2a and 2b is represented by the equation

Eq. (2) in [1]

Enthalpy for given entropy on the boundary line of subregions 2a and 2b

Eq. (2) in [1]

Determination of subregion

Subregion of region 2 for given specific enthalpy and specific entropy is

Pressure

References

1. 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. Gaithersburg,

Maryland, USA, September 2001, available at http://www.iapws.org