functiondensity_pTX

Density of air as a function of pressure, temperature and species concentration

Extends from Modelica.Icons.Function (Icon for functions).

Information

Function to compute the density of moist air for given pressure, temperature and water vapor mass fraction.

Note that the water vapor mass fraction is in kg/kg total air.

Inputs

TypeNameDefaultDescription
Modelica.Units.SI.PressurepAbsolute pressure of the medium
Modelica.Units.SI.TemperatureTDry bulb temperature
Modelica.Units.SI.MassFractionX_wWater vapor mass fraction per unit mass total air

Outputs

TypeNameDefaultDescription
Modelica.Units.SI.DensitydMass density

Revisions

  • September 19, 2025, by Michael Wetter:
    Inlined function, as this function is often used by the multizone airlfow models. This further improves the computing time.
    This is for IBPSA, #2043.
  • November 23, 2015 by Filip Jorissen:
    Added derivative information for avoiding numerical Jacobians.
  • February 24, 2015 by Michael Wetter:
    First implementation.