Modeling Droplet Evaporation

The Droplet Evaporation Rate models account for mass transfer due to evaporation and condensation.

The steps in this procedure are intended to follow on from Step 4 in Modeling Bubbly and Droplet Flows.

To make the evaporation models available, you must define one multi-component gas phase and one liquid phase. The liquid phase can be single component or multi-component. In the phase interaction, the Continuous Phase must be the gas phase, and the Dispersed Phase must be the liquid phase.

Mass transfer occurs when the system departs from the equilibrium condition (Eqn. (2048)). Evaporation occurs when the gas bulk mole fraction of the evaporating component is below the equilibrium value; otherwise condensation occurs.

The Single Component Droplet Evaporation Rate model is used for single component (pure fluid) droplets. For multiple component droplets, the Multicomponent Droplet Evaporation Mass Transfer Rate model is used. This model assumes that the liquid drops are internally homogeneous and that the liquid behaves like an ideal mixture. The presence of inert components is allowed in both the gas and the liquid.

To model droplet evaporation:

  1. In the phase interaction, select the following models in addition to the models that you previously selected:
    Group Box Model

    Reaction Regime

    Non-reacting (applies to multi-component phases only)

    Optional Models

    		Interphase Mass Transfer
  2. In the Interphase Mass Transfer Rate group box, select Single Component Droplet Evaporation Rate or Multicomponent Droplet Evaporation Mass Transfer Rate, whichever is applicable.
  3. Select the Droplet Evaporation Mass Transfer Rate node and specify the relevant property settings.

    See Droplet Evaporation Rate Model Reference.

The following step applies to Multicomponent Droplet Evaporation only.

  1. Set the Phase 0 Components property to specify the relationship between the phase components.

    You match the components of the continuous phase (in the left-hand column) with the components of the dispersed phase in the right-hand column.

    For each transfer activated, the continuous phase component name appears under the Equilibrium Coefficient > Composite node.

  2. In the Continuous Phase Sherwood Number and Continuous Phase Nusselt Number nodes, specify the appropriate settings.

    See Sherwood Number Properties and Nusselt Number Properties.

  3. In the Equilibrium Coefficient > Composite node, specify the appropriate equilibrium coefficients.

    See Equilibrium Coefficient Properties.

Return to Modeling Bubbly and Droplet Flows and continue with Step 4.