Dispersed Phase Boundary Condition Equations

Dispersed Phase Boundary Condition Equations

In addition to the boundary conditions for the mixture, specify boundary conditions for the dispersed phase on Wall, Inlet, and Outlet nodes. For these boundary types, the boundary condition’s Settings window contains a Dispersed Phase Boundary Condition section.

Dispersed Phase Concentration

This is the default for the Inlet node. Specify the dispersed phase volume fraction:

Enter the (dimensionless) in the

field.

If is selected under the section, the dispersed phase number density is also specified. The dispersed phase number density can be specified directly,

or, when is selected, computed from the diameter of particles and droplets dd:

Dispersed Phase Outlet

This is the default for the Outlet node. This boundary condition is appropriate for boundaries where the dispersed phase leaves the domain with the dispersed phase velocity ud. No condition is imposed on the volume fractions at the boundary.

A corresponding flux condition is also applied for the number density equation (when is selected under the section).

Dispersed Phase Flux

Using this boundary condition, specify the dispersed phase flux through the boundary:

Enter the (SI unit: m/s) in the

field.

If is selected under the section, the number density flux through the boundary is also specified:

This boundary condition, which is useful on boundaries that represent a symmetry line for the dispersed phase, sets the dispersed phase flux through the boundary to zero:

A corresponding flux condition is also applied for the number density equation (when is selected under the section).

No Dispersed Flux

This is the default for the Wall node. This boundary condition represents boundaries where the dispersed phase flux through the boundary is zero:

In the case of moving Wall and Interior Wall, the dispersed flux through the boundary is:

This implies that the flux, relative to the boundary motion, is zero. A corresponding flux condition is also applied for the number density equation (when is selected under the section).