IAPWS#

Introduction#

The API defines convenient functions and subroutines for computing water physico-chemical properties.

Value at the critical point#

Critical values are available as constants [1]:

water:
- Tc_H2O
- rhoc_H2O
- pc_H2O
In heavywater
- Tc_D2O
- rhoc_D2O
- pc_D2O

Henry’s Constant and Vapor-Liquid Distribution Constant for Gases in H2O and D2O#

The Henry constant kh and the liquid-vapor distribution constant kd can be computed for the following gases as defined in [2] :

in water: He, Ne, Ar, Kr, Xe, H2, N2, O2, CO, CO2, H2S, CH4, C2H6, SF6
in heavywater: He, Ne, Ar, Kr, Xe, D2, CH4

The available gases can be retrieved with

gases which returns the available gases as a list.
gases2 which return the available gases as a string.
ngases which returns the number of available gases.

_images/g704-kh_H2O.png — \(k_H\) in \(H_2O\)#

_images/g704-kh_D2O.png — \(k_H\) in \(D_2O\)#

_images/g704-kd_H2O.png — \(k_D\) in \(H_2O\)#

_images/g704-kh_D2O.png — \(k_D\) in \(D_2O\)#

Thermodynamic Properties of Water and Steam#

Five regions which cover the following range of validity [3]:

\(273.15K < T < 1073.15K\) and \(p < 100MPa\)
\(1073.15K < T < 2273.15K\) and \(p < 50MPa\)

_images/iapws_r797-regions.png — Water regions defined in R7-97#

The saturation-pressure psat and the saturation-temperature Tsat computes the saturation line as shown in the plot below.

_images/r797-r4.png — Saturation line.#