Defining the Phase Interactions

Define the interactions between the phases.

Using the Multiphase Interaction model, you can define the interaction between the liquid and vapor phases.

When you create a phase interaction, you select the continuous phase first, and then the dispersed phase. When you select the dispersed phase, you also choose the phase interaction type. In this simulation, the continuous phase is Liquid, the dispersed phase is Vapor, and the phase interaction type is Continuous-Dispersed Topology.

To define the phase interactions:

  1. In the Coolant continuum, right-click the Models > Multiphase Interaction > Phase Interactions node and select New > Liquid > Vapor (Continuous-Dispersed).
  2. Rename the Phase Interaction 1 node to Liquid Vapor Interface.
  3. For the Liquid Vapor Interface phase interaction, select the following models in order:
    Group Box Model
    Optional Models

    Turbulent Dispersion Force

    Virtual Mass Coefficient (selected automatically)

    Optional Models Interphase Mass Transfer
    Interphase Mass Transfer Rate Boiling Mass Transfer Rate
    Optional Models

    Wall Boiling

    Wall Bubble Nucleation (selected automatically)

    Wall Transient Conduction (selected automatically)

  4. Click Close.

    The Liquid Vapor Interface > Models node is shown below:



Select a more appropriate interaction length scale model.
  1. Select the Liquid Vapor Interface > Models > Interaction Length Scale > Interaction Length Scale node and set the Method property as Kurul Podowski .

Define the remainder of the phase interaction properties.

  1. Edit the Liquid Vapor Interface > Models node and set the following properties:
    Node Property Setting
    Boiling Mass Transfer Rate > Continuous Phase Nusselt Number Method Ranz-Marshall
    Multiphase Material > Material Properties > Boiling Temperature > Constant Value 560.65 K
    Multiphase Material > Material Properties > Surface Tension > Constant Value 0.01725 N/m
    Drag Force > Drag Coefficient Method Tomiyama

    Selecting the Ranz-Marshall option makes Simcenter STAR-CCM+ calculate the Nusselt number using the Ranz-Marshall correlation. The Nusselt number is used to calculate the heat transfer coefficient for the heat transfer from the bulk water to the bubble interface.

    The interface temperature is the saturation temperature of the liquid phase.

    The Tomiyama model is appropriate for modeling a small bubble in a low viscosity, air-water system.

  2. Save the simulation.