Time derivative of density derivative along phase boundary
function drhovl_dp_der extends Modelica.Icons.Function; input Units.SI.Pressure p "saturation pressure"; input ThermoSysPro.Properties.WaterSteam.Common.IF97PhaseBoundaryProperties3rd bpro "property record"; input Real p_der "Time derivative of pressure"; output Real dd_dp_der "derivative of density along the phase boundary"; end drhovl_dp_der;