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Thermodynamic Properties of Ordinary Water Substance for Industrial Use

in region 2 of IAPWS-IF97:

Backward Equations: T(p, 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

"Revised Release on the IAPWS Industrial Formulation 1997 for the Thermodynamic Properties of Water and Steam" [1] (named as IAPWS-IF97)

provided by IAPWS.

Detailed information about used equations, constants, range of validity etc is presented in PDF version of IAPWS document which can be downloaded from IAPWS web site www.iapws.org

Authors (and responsible persons):

Moscow Power Engineering Institute (MPEI). Last update: 2013/01/09

Note that displayed last digits depends on numeric implementation of underlying formulations.

Input parameters

Formulation reference values

Dimensionless input parameters

Main backward equations

The temperature in subregion 2a is represented by the equation

Eq. (25) in [1]

Coefficients from Table 25 [1] (can be downloaded here in text format):

Extracting data to vectors:

The dimensionless temperature in subregion 2a

The temperature in subregion 2b is represented by the equation

Eq. (26) in [1]

Coefficients from Table 26 [1] (can be downloaded here in text format):

The dimensionless temperature in subregion 2b

The temperature in subregion 2c is represented by the equation

Eq. (27) in [1]

Coefficients from Table 27 [1] (can be downloaded here in text format):

The dimensionless temperature in subregion 2c

Eq. (24) in [1]

Determining the subregion

Subregion of region 2 for given entropy and pressure is

Dimensionless temperature

Temperature

References

1. Revised Release on the IAPWS Industrial Formulation 1997 for the Thermodynamic Properties of Water and Steam. Lucerne, Switzerland, August 2007, available at http://www.iapws.org