This function is based on the kinetic theory of gases under the following assumptions [Present1958]:
Also, it is assumed that the Einstein relation applies.
Please see [Davies2013, Ch. 3] for a derivation of the rate of phase change from kinetic theory.
Although specific volume is an input to this function, the result is independent of specific volume.
function tauprime extends Modelica.Icons.Function; input Q.TemperatureAbsolute T = 298.15*U.K "Temperature" annotation( Dialog(__Dymola_label = "<html><i>T</i></html>")); input Q.VolumeSpecific v = 298.15*U.K/p0 "Specific volume" annotation( Dialog(__Dymola_label = "<html><i>v</i></html>")); output Q.TimeAbsolute tauprime "Phase change interval" annotation( Dialog(__Dymola_label = "<html>τ′</html>")); end tauprime;