This calculates several specific properties of water at temperature and pressure according to the IAPWS Industrial Formulation 1997.
International Association for the Properties of Water and Steam – Revised Release on the IAPWS Industrial Formulation 1997 for the Thermodynamic Properties of Water and Steam (2007)
Kelton calculation reference C160
FLOCALC calculation reference F057
KIMS calculation reference K154
- Full calculation
- Boundary condition calculation
This option is chosen to select the whether to calculate the array of water properties listed below (full) or to solve the boundary conditions so that the correct region can be selected when attempting the full calculation.
- Region 1
- Region 2
- Region 3
- Region 5
This option is used to select which region, as defined by the temperature and pressure, the calculation is to use. Note that other than Region 3 pressure and temperature are the required inputs. Region 3 uses density in place of pressure.
Boundary condition calculation
- Region 2/3 boundary condition
- Region 4 saturation line
This option is used to select which boundary to solve for. Note Region 4 saturation line forms the boundary between Region 1 and Region 2.
This option is used to select which variable is to be solved when calculating the boundary between regions.
Specific gas constant of ordinary water R = 0.461526 kJ kg-1K-1
Temperature of water at critical point Tc = 647.096 K
Pressure of water at critical point Pc = 22.064 MPa
Density of water at critical point ρc = 322 kg m-3
Temperature of water at triple point Tt = 273.16 K
Pressure of water at triple point Pt = 611.657 Pa
The calculation calculates the quantities:
- Specific volume
- Specific enthalpy
- Specific internal energy
- Specific entropy
- Specific isobaric heat capacity
- Specific isochoric heat capacity
- Speed of sound
and depending on the options selected
- Specific Gibbs free energy
- Specific Helmholtz free energy
The inputs and input logic are used to determine which of the region equations given by IF-97 (2007) the calculation needs to use. Then a series of calculations are done using dimensionless derivatives of the free energy equations to calculate the above quantities.