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Viscosity of Ordinary Water Substance Calculation

based on equations for general and scientific use

Developed by Russian National Committee (RNC) of

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

This calculation page is based on the

"Release on the IAPWS Formulation 2008 for the Viscosity of Ordinary Water Substance" [1]

provided by IAPWS.

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

Authors (and responsible persons):

Moscow Power Engineering Institute (MPEI). Last update: 2012/09/21

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

Input parameters

Formulation reference values

Dimensionless input parameters

Main equation

The viscosity is represented by the equation

Eq. (10) in [1]

First factor

This factor represents the viscosity in the dilute-gas limit.

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

Eq. (11) in [1]

Second factor

The second factor represents the contribution to viscosity due to finite density.

Coefficients from Table 2 [1] (can be downloaded here in text format):

Eq. (12) in [1]

Critical enhancement

The critical enhancement is only significant in a very small region in density and temperature around the critical point.

Additional constants from Table 3 [1]:

Additional thermophysical properties for given pressure and temperature

Derivative of density on pressure at constant temperature (calculated using RNC implementation of [2]):

Dimensionless isothermal compressibility:

Derivative of density on pressure at constant temperature at relative reference temperature T_{R}:

Dimensionless isothermal compressibility at relative reference temperature T_{R}:

Eq. (21) in [1]

When this value is less than zero, it must be set to zero for calculations to proceed.

Correlation length:

Eq. (20) in [1]

Eq. (17) in [1]

Eq. (19) in [1]

Eq. (18) in [1]

Eq. (15) and (16) in [1]

The critical enhancement is

Eq. (14) in [1]

Results

relative viscosity:

viscosity:

where:

without critical enhancement:

critical enhancement:

References

1. Release on the IAPWS Formulation 2008 for the Viscosity of Ordinary Water Substance. Berlin, Germany September 2008, available at http://www.iapws.org

2. Revised Release on the IAPWS Formulation 1995 for the Thermodynamic Properties of Ordinary Water Substance for General and Scientific Use, available at http://www.iapws.org (2007).