WaterSteamPro has a function set for calculation of thermodynamic properties, coefficient of surface tension, kinematic and dynamic viscosities, thermal conductivity, Prandtl number, isentropic exponent, Joule-Thomson coefficient for water and steam at saturation line, one-phase and double-phase areas, etc.
All the thermodynamic properties are calculated by Formulation IF-97 [2]. At that, all the values of thermodynamic properties of water and steam at saturation line at temperatures above 350 °C (pressure above 16,5 MPa) are calculated by implicit equation for IF-97 region 3 with values of temperature and pressure, defined by the equation for saturation line (IF-97 region 4). All the thermodynamic functions include temperature range from 0.01 to 2000°C at pressure up to 10 MPa and from 0.01 to 800°C at pressure up to 100 MPa.
Dynamic viscosity of water and steam at saturation line is calculated by equation IAPWS-85 [5], corrected for temperature scale ITS-90. The range of validity (according to IAPWS) is for pressure up to 500 MPa temperature is from 0 to 150°C, for pressure up to 350 MPa temperature is from 150 to 600°C, for pressure up to 300 MPa temperature is from 600 to 900°C. Density values which are the arguments of the equation are defined by Formulation IF-97 for given temperature and pressure.
The values of kinematic viscosity are calculated by the equation:
ν = μ / ρ
where: μ - dynamic viscosity which is defined by equation described above, ρ - density which is the value inverse to specific volume calculated by Formulation IF-97.
Thermal conductivity of water and steam at saturation line is calculated by equation IAPWS-85, recommended for industrial use [6], and corrected for temperature scale ITS-90. At that, the density values, which are the arguments of the equation as for dynamic viscosity, are calculated by Formulation IF-97. The range of validity corresponds with recommendations of IAPWS: at temperature from 0.01 to 800°C and pressure up to 40 MPa, at temperature from 0.01 to 650°C and pressure from 40 to 70 MPa, at temperature from 0.01 to 500°C and pressure from 70 to 100 MPa.
The Prandtl number is calculated as:
Pr = (μ·Cp) / λ
where: μ - dynamic viscosity; Cp - specific isobaric heat capacity defined by Formulation IF-97; λ - thermal conductivity defined by IAPWS formulation from 1985. The range of definition corresponds with range of definition of equation for thermal conductivity.
Isoentropic exponent is calculated as:
K = w * w / (p * v)
where: w - sound velocity; p - pressure; v - specific volume. The range of parameters corresponds with IF-97.
Joule-Thomson coefficient (JT = (dt/dp)h) is calculated by equation which is specific for each region of the IF-97.