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.
function density_pTX extends Modelica.Icons.Function; input Modelica.SIunits.Pressure p "Absolute pressure of the medium"; input Modelica.SIunits.Temperature T "Dry bulb temperature"; input Modelica.SIunits.MassFraction X_w "Water vapor mass fraction per unit mass total air"; output Modelica.SIunits.Density d "Mass density"; end density_pTX;