.Modelica.Fluid.Dissipation.Utilities.Types.VoidFractionApproach .Modelica.Fluid.Dissipation.Utilities.Types.VoidFractionApproachtype VoidFractionApproach = enumeration(Homogeneous "Homogeneous approach", Momentum "Analytical momentum flux approach (heterogeneous)", Energy "Kinetic energy flow approach w.r.t. Zivi (heterogeneous)", Chisholm "Empirical momentum flux approach w.r.t. Chisholm (heterogeneous)");