Interfacial Area

When the Solve for interfacial area check box is selected on The Mixture Model, Laminar Flow Interface or The Turbulent Bubbly Flow Interface Settings window (under the Physical Model section), it is also possible to compute the interfacial area per volume the number density n is known, that is, the number of dispersed particles per volume. It adds the following equation for the number density n:

nt + nud = 0

This equation states that a dispersed phase particle cannot disappear, appear, or merge with other particles, although it may expand or shrink.

The Mixture Model interface calculates the interfacial area a (SI unit: m2/m3) from the following equation:

a = 4n 1 3 3 d 2 3

Initial Values

The Initial Values feature adds initial values for the mixture velocity, pressure, and volume fraction of the dispersed phase, that can serve as an initial condition for a transient simulation or as an initial guess for a nonlinear solver.

D O M A I N S E L E C T I O N

From the Selection list, choose the domains to define an initial value.

I N I T I A L V A L U E S

Enter values or expressions for the following dependent variables:

•Velocity field, mixture components u (SI unit: m/s)

•Pressure p (SI unit: Pa)

•Volume fraction, dispersed phase (unitless)

•If a Schiller-Naumann slip model is applied; enter an initial value for the Squared slip velocity U2slip (SI unit: m2/s2)

•If Solve for interfacial area check box is selected; enter an initial value for the Number density, dispersed phase nd (SI unit: 1/m3)

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