Thermophysical Properties of Liquid Water & Steam in Seeq

Overview

Thermophysical properties of water (liquid and steam) are commonly calculated across a variety of verticals.

Seeq provides a collection of functions for calculating liquid water and steam properties based on an implementation of IAPWS-IF97.

Each function takes two input items and returns a specific property.

The default unit for each item type is specified in the list below, but the functions accept other compatible units. The formula operator identifies the type of input provided based on the units associated with the input. If other compatible units are provided they get converted to the default units in the backend except for pressure signals which require unit conversion to absolute pressure.

Default input item units:

absolute pressure, MPa (As a reminder, absolute pressure = gage pressure + atmospheric pressure)
specific enthalpy, kJ/kg
specific entropy, kJ/kg/K
temperature, K
density, kg/m³

Here is the list of functions available in the Seeq Formula tool. Refer to the formula documentation in workbench for more details on individual functions.

Available Functions

IF97_absolutePressure()-Compute the absolute pressure according to IAPWS-IF97 standard.
IF97_density()-Compute the density according to IAPWS-IF97 standard.
IF97_dielectricConstant()-Compute the dielectric constant according to IAPWS-IF97 standard.
IF97_dynamicViscosity()-Compute the dynamic viscosity according to IAPWS-IF97 standard.
IF97_isobaricCubicExpansionCoefficient()-Compute the isobaric cubic expansion coefficient according to IAPWS-IF97 standard.
IF97_isothermalCompressibility()-Compute the isothermal compressibility according to IAPWS-IF97 standard.
IF97_kinematicViscosity()-Compute the kinematic viscosity according to IAPWS-IF97 standard.
IF97_partialDerivative()-Compute the partial derivative of state properties with respect to the known properties according to IAPWS-IF97 standard.
IF97_PD-Constants defining the quantities for partial derivatives
IF97_PrandtlNumber()-Compute the Prandtl number according to IAPWS-IF97 standard.
IF97_specificEnthalpy()-Compute the specific enthalpy according to IAPWS-IF97 standard.
IF97_specificEntropy()-Compute the specific entropy according to IAPWS-IF97 standard.
IF97_specificGibbsFreeEnergy()-Compute the specific Gibbs free energy according to IAPWS-IF97 standard.
IF97_specificInternalEnergy()-Compute the specific internal energy according to IAPWS-IF97 standard.
IF97_specificIsobaricHeatCapacity()-Compute the specific isobaric heat capacity according to IAPWS-IF97 standard.
IF97_specificIsochoricHeatCapacity()-Compute the specific isochoric heat capacity according to IAPWS-IF97 standard.
IF97_specificVolume()-Compute the specific volume according to IAPWS-IF97 standard.
IF97_speedOfSound()-Compute the speed of sound according to IAPWS-IF97 standard.
IF97_surfaceTension()-Compute the surface tension according to IAPWS-IF97 standard.
IF97_temperature()-Compute the temperature according to IAPWS-IF97 standard.
IF97_thermalConductivity()-Compute the thermal conductivity according to IAPWS-IF97 standard.
IF97_thermalDiffusivity()-Compute the thermal diffusivity according to IAPWS-IF97 standard.
IF97_vaporQuality()-Compute the vapor quality according to IAPWS-IF97 standard.

Instructions

An example of how to compute density according to the IAPWS-IF97 standard:

1. Add the pressure and temperature signals to details pane (i.e., load the signals so that they appear in the trend).

2. Open the Formula tool and type “IF97_density()” in the Formula documentation pane.

3. Click the “copy” button by the first example. Make sure the variable names ($name) for the pressure and temperature signals (‘$p’ and ‘$t’ respectively in the figure below) match between the function and the Variable list above. Click “Execute”.

4. The calculated density signal appears as a new signal.