Working with Injectors

In Simcenter STAR-CCM+, particles enter the fluid continuum through injectors. While the Lagrangian phase defines what particles enter the domain and how they behave, the injector defines where, in what direction, and with what frequency, the particles enter.

Injectors are contained within a top-level injectors manager node.

The following types of injector are currently provided in Simcenter STAR-CCM+:

  • The Part injector generates a cloud of injection points that are positioned according to the geometry of the parts you select.
  • The Point injector injects particles from a single point in a direction you specify.
  • The Hollow Cone injector injects particles from a single point, with inner, and outer angles you specify.
  • The Solid Cone injector injects particles from a single point, with only the outer angle you specify.
  • The Surface injector injects particles from the face centroids of a geometric surface you select.
  • The Nozzle injector is used with the Linear Instability Sheet Atomization (LISA), Huh, and Droplet Flash-Boiling models to inject particles from a nozzle of dimensions you specify.
  • The Lattice injector is used with the Discrete Element Method (DEM) to inject particles into the system with specified, mesh-independent spatial distribution.
  • The Random injector is used with the Discrete Element Method (DEM) to inject particles into a region with a random point distribution. The Particle Packing Specification controls the number of particles that are injected.
  • The Parcel Transfer injector is used to reinject parcels of one phase as parcels of another, according to criteria you specify.
  • The Film Stripping injector is used with the Fluid Film model, to simulate droplets being formed and removed from the surface of a fluid film. Both wave stripping and edge stripping can contribute to this phenomenon.

These types are explained in greater detail in the section, Understanding Injector Types. Further documentation is provided in:

Injectors Manager Node

Injector nodes represent injectors and are all contained within the Injectors manager node, which has properties and its own pop-up menu. The injector manager can hold any number of injectors up to the memory limits of the computer.



Injector Manager Expert Properties

Tree Threshold Specifies the maximum estimated number of injection points per region before the algorithm changes to a tree search. There is a memory and CPU time penalty that is incurred in building the tree. If there are enough points, the algorithm repays this penalty by using the tree search to locate the points faster than the default brute-force algorithm.

Post-Processing Injected Quantities

To keep data from an injector for post-processing, activate the Retain Injected Parcels property of the injector.

An injector can be used for post-processing in any eligible report using the Parts property, as well as in plots, scene displayers, and simulation history files. Injectors are listed among the available parts. Injectors cannot be selected as inputs for threshold parts or parcel data mappers. A report gives an Unable to compute message if the selected injector has the Lagrangian Phase property set to None.

If DEM Particles Clumps are specified as the Lagrangian phase of the injector, the injector data for post-processing contains parcels where each parcel represents a clumped particle, and not the sub-parcels of each clump.