Impingement Model Reference

The Impingement model is used to model the impingement of a Lagrangian phase on a VOF free surface or a MMP continuous phase. The model conserves fluid volume.

Depending on the multiphase model you are using to model Lagrangian impingement, Simcenter STAR-CCM+ incorporates the following impingement criteria for each model:
Multiphase Model Impingement Criteria
Volume of Fluid (VOF) Impingement occurs once a Lagrangian parcel enters a cell where the volume fraction of the receiving VOF phase is 0.5 and one of the following conditions are met:
  • The Eulerian phase has a small interface area density, where ‖ ∇ α c ‖ ≤ 0.1 h c , indicating that the parcel is away from an interface, but within the liquid phase. h c is the characteristic cell length scale.
  • The Eulerian phase has a large interface area density and v p ⋅ n c < 0 , indicating that the parcel is at the interface and heading into liquid. v p is the parcel velocity and n c is the interface normal vector of the Eulerian phase in the corresponding cell.
Mixture Multiphase (MMP) Impingement occurs once the droplet of parcel enters a cell where the volume fraction of the receiving continuous phase exceeds a user-defined threshold.
Provided By Multiphase Interaction > Phase Interactions > [phase interaction] > Models > Optional Models
Example Node Path Multiphase Interaction > Phase Interactions > [phase interaction] > Models > Impingement
Requires One of the following:
  • For a Volume of Fluid (VOF) Multiphase simulation, a VOF-Lagrangian Phase Interaction must be defined.
  • For a Mixture Multiphase (MMP) simulation, a MMP-Lagrangian Phase Interaction must be defined.
Time
  • Implicit Unsteady
  • PISO Unsteady
  • Steady
Properties For an MMP-Lagrangian Phase Interaction:
  • Volume Fraction Threshold
See Impingement Properties.
Activates Boundary Inputs MMP Conversion, VOF Conversion become available on the Mode node for:
  • The Lagrangian phase, Boundary Conditions > Boundary Conditions > [boundary] > Physics Conditions.

  • For each boundary, Boundaries > Phase Conditions > [phase] > Physics Conditions.

    See the MMP Conversion and VOF Conversion

Field Functions See Impingement Field Functions.

Impingement Properties

Available for a MMP-Lagrangian phase interaction only.

Volume Fraction Threshold
Specifies the volume fraction threshold for the impingement of the Lagrangian phase onto the MMP continuous phase. A Lagrangian particle impinges onto the MMP continuous phase if the volume fraction of the MMP phase in the corresponding cell is larger than this value. The default value is 0.7.

Impingement Field Functions

The following field function are available with the Impingement phase interaction model:
Continuity Source of [Eulerian phase]
The rate of mass transfer from the Lagrangian phase to the Eulerian phase through phase interaction.
Energy Source
The rate of energy transfer from the Lagrangian phase to the Eulerian phase through phase interaction.
Momentum Source
The rate of momentum transfer from the Lagrangian phase to the Eulerian phase through phase interaction.
Mass Source [component] of [Eulerian phase]
The rate of mass transfer from the Lagrangian component to the corresponding component in the Eulerian Phase.
Impingement Rate of [Eulerian phase]
The rate of impingement from the Lagrangian phase to the Eulerian phase.
The following field functions are made available to the simulation with the VOF-Lagrangian Phase Interaction and when the Temporary Storage Retained property is activated for the Lagrangian multiphase solver:
Interface Area Density of [Eulerian phase]
The interfacial area available for momentum, heat, and mass transfer from the Lagrangian phase to the continuous Eulerian phase.
Interface Normal of [Eulerian phase]
The unit normal vector ( − ∇ α c ‖ ∇ α c ‖ ) pointing away from the Eulerian phase.