if97: IAPWS-IF97 Equations for Regions 1, 2, 3 and 5

In iapws: Formulations of the International Association for the Properties of Water and Steam

IAPWS-IF97 Equations for Regions 1, 2, 3 and 5

Description

Compute thermodynamic and transport properties of water and steam using the IAPWS industrial formulation 1997.

Usage

if97(what, p, t, h, state = NULL)

Arguments

what	a character vector listing the output properties. See Details for available properties.
p	a numeric vector giving the pressure values in MPa.
t	a numeric vector giving the temperature values in K.
h	a numeric vector giving the specific enthalpy values in kJ/kg.
state	NULL or a character vector giving the physical state. One of "liquid", "gas" or "supercritical". In case of NULL, the state is determined by the function if97_state().

Details

The available properties for what are:

• "f": the specific free energy in kJ/kg.

• "g": the specific Gibbs enthalpy in kJ/kg.

• "u": the specific internal energy in kJ/kg.

• "h": the specific enthalpy in kJ/kg.

• "s": the specific entropy in kJ/K/kg.

• "t": the temperature in K.

• "p": the pressure in MPa.

• "v": the specific volume in m^3/kg.

• "rho": the mass density in kg/m^3.

• "cv": the specific isochoric heat capacity in kJ/K/kg.

• "cp": the specific isobaric heat capacity in kJ/K/kg.

• "alpha": the expansion coefficient in 1/K

• "beta": the pressure coefficient in MPa/K.

• "kappat": the isothermal compressibility in 1/MPa.

• "w": the speed of sound in m/s.

• "eta": the dynamic viscosity in \muPa.s.

• "lambda": the thermal conductivity in mW/K/m.

A valid pair of p, t and h is needed: either (p, t) or (p, h).

Value

A numeric matrix of dimension c(n, length(what)) with n the maximum length of either p, t, h or state.

Note

Computing several properties in a single call may be more efficient than separately because most of the computation time is shared.

Author(s)

Jonathan Debove

References

International Association for the Properties of Water and Steam, IAPWS R7-97(2012), Revised Release on the IAPWS Industrial Formulation 1997 for the Thermodynamic Properties of Water and Steam.

International Association for the Properties of Water and Steam, IAPWS R12-08(2008), Release on the IAPWS Formulation 2008 for the Viscosity of Ordinary Water Substance.

International Association for the Properties of Water and Steam, IAPWS R15-11(2011), Release on the IAPWS Formulation 2011 for the Thermal Conductivity of Ordinary Water Substance.

Examples

what <- c("v", "h", "u", "s", "cp", "w")

# Region 1 Tab. 5
tab5 <- if97(what, t = c(300, 300, 500), p = c(3, 80, 3))
format(tab5, scientific = TRUE, digits = 9)

# Region 2 Tab. 15
tab15 <- if97(what, t = c(300, 700, 700), p = c(3.5e-3, 3.5e-3, 30))
format(tab15, scientific = TRUE, digits = 9)

# Region 2 metastable Tab. 18
tab18 <- if97(what, t = c(450, 440, 450), p = c(1, 1, 1.5), state = "gas")
format(tab18, scientific = TRUE, digits = 9)

# Region 3 Tab. 33
tab33 <- if97(what, t = c(650, 650, 750),
              p = c(0.255837018e2, 0.222930643e2, 0.783095639e2))
format(tab33, scientific = TRUE, digits = 9)

# Region 5 Tab. 42
tab42 <- if97(what, t = c(1500, 1500, 2000), p = c(0.5, 30, 30))
format(tab42, scientific = TRUE, digits = 9)



# Viscosity and thermal conductivity
what <- c("lambda", "eta")

# Region 1 Tab. 7
tab7 <- if97(what, p = c(20, 50), t = c(620, 620))
format(tab7, scientific = TRUE, digits = 9)

# Region 2 Tab. 8
tab8 <- if97(what, p = c(0.3, 50), t = c(650, 800))
format(tab8, scientific = TRUE, digits = 9)

## Region 3 Tab. 9
#tab9 <- if97_rhot(c("lambda", "rho", "cp", "cv", "eta"),
#      rho = c(0.3, 50), t = c(222, 322)),
#format(tab9, scientific = TRUE, digits = 9)

iapws documentation built on June 8, 2025, 11:14 a.m.