Modeling Fluid Film Boiling

To model fluid film boiling, you set up a Film-Physics continuum phase interaction model, activate the fluid film Boiling model, and set the property values according to your simulation.

To set up a fluid film boiling simulation you can start from the default model selections and calibrations. If suitable experimental data is available, the boiling properties can also be calibrated or replaced with user-defined relationships.

High heat flux wall boiling cases can sometimes fail to converge, in such cases some troubleshooting might be required. For more information, see Troubleshooting Fluid Film Boiling Simulations.

You are required a simulation with the Fluid Film model activated in the physics continuum.
To set up a Fluid Film Boiling simulation:
  1. Select the physics models that are required for a fluid film simulation. Include the following models:
    • Multi-Component Gas material model in the physics continuum.
    • Multiphase Interaction model in the physics continuum.
    • Select either Segregated Fluid Enthalpy or the Segregated Fluid Energy models.
  2. Create a Film-Physics Continuum Interaction multiphase interaction and select the Fluid Film phase.
  3. In the Film-Physics Continuum Interaction phase interaction select the following models:
    Group Box Model

    Optional Models

    		Multiphase Material
    Component Mapping
  4. Select the Phase Interaction Model Selection dialog, in the Boiling Model group box, select one of the following:

    • Habchi Boiling

      The Habchi boiling model accounts for the vaporization of liquid films across liquid film evaporation, nucleate, and transition boiling phases. The model distinguishes between these stages based on saturation, Nukiyama, and Leidenfrost temperatures. Furthermore, the model adjusts the evaporation rate of the liquid to accommodate the impact of ambient gas pressure and wall roughness.

    • Rohsenow Boiling

      A nucleate boiling model which provides a correlation between the heat flux, the temperature difference between the surface and the bulk liquid. Nucleate boiling involves the creation and growth of vapor bubbles on a heated surface, which rise from discrete points on a surface. Film boiling occurs when the critical heat flux is exceeded and a continuous vapor film covers the heated surface.

      See Fluid Film Boiling Models Reference.

  5. If you are using the Habchi Boiling model, select the [phase interaction] > Models > Habchi Boiling node and set the Dry Area Fraction.

    See Habchi Boiling Model Properties.

  6. Expand the Habchi Boiling node and set the following:
  7. If you are using the Rohsenow Boiling model, select the [phase interaction] > Models > Rohsenow Boiling node and set the model properties.
  8. Expand the Rohsenow Boiling node and set the HTCxArea for the heat transfer coefficient between the vapor bubbles and the surrounding liquid.

The boiling model has to know the critical pressure and temperature for the film liquid components, and the latent heat of vaporization. The latent heat of vaporization is the difference between the enthalpies of the vapor and the liquid at the saturation temperature.

  1. Set the material properties of liquid components of the fluid film phase.

    The important properties are:

    • Critical Temperature
    • Critical Pressure
    • Heat of Formation
    • Latent Heat of Vaporization
    • Saturation Pressure
    • Standard State Temperature

    See Material Properties.

Fluid film boiling models have to know the Leidenfrost temperatures for the multi-component liquid film. The Habchi boiling model also requires the Nukiyama temperature.

  1. Set the Leidenfrost Temperature and Nukiyama Temperature material properties of the multi-component liquid phase.