The Rotating Machinery, Mixture Model, k-ε (mm) interface () is used to model high Reynolds number flow of a multiphase mixture in equipment containing one or more rotating parts. The mixture consists of a liquid with dispersed particles, bubbles, liquid droplets, or solid particles, which are assumed to always travel with terminal velocity.

The interface solves one set of Navier–Stokes equations for the momentum of the mixture. The pressure distribution is calculated from a mixture-averaged continuity equation and the velocity of the dispersed phase is described by a slip model. The dispersed particles are tracked by solving a transport equation for the volume fraction of the dispersed phase. Turbulence effects are modeled using the standard two-equation k-ε model with realizability constraints. Flow close to walls is modeled using wall functions.

There are two study types available for this physics interface. For the Time Dependent study type the rotation is achieved by moving mesh functionality, also known as sliding mesh. For the Frozen Rotor study type the rotating parts are kept frozen in position, and the rotation is accounted for by the inclusion of centrifugal and Coriolis forces.

When this physics interface is added, the following default nodes are also added in the Model Builder, under Mixture Model, k-ε — Mixture Properties, Wall, and Initial Values. A Moving Mesh interface with a Rotating Domain node is added automatically in the Model Builder under the Definitions node. Then, from the Physics toolbar, add other nodes that implement, for example, boundary conditions. You can also right-click Mixture Model, k-ε to select physics features from the context menu.

The physics interface settings are the same as described for The Rotating Machinery, Mixture Model, Laminar Flow Interface, for Moving Mesh, and for The Mixture Model, k-ε Interface in the CFD Module User’s Guide.