Return density from p and T
function density_pTX extends Modelica.Icons.Function; input AbsolutePressure p "Pressure"; input Temperature T "Temperature"; input MassFraction X[nX] "Mass fractions"; input Integer phase = 1 "2 for two-phase, 1 for one-phase, 0 if not known"; output Density d "Density"; end density_pTX;