18.4. Supported Capabilities and Limitations

The following functions are available in the CFX-Solver for evaluations of quantities over injection positions:

  • area, areaAve, areaInt

  • ave

  • count

  • inside()

  • massFlow, massFlowAve, massFlowAveAbs, massFlowInt

  • maxVal,minVal

  • rmsAve

  • sum

For example, for an injection region that lies on a surface, the area function returns the total area of all injection holes of the injection region.

Like other CEL functions, the functions listed above return conservative values by default. That is, the returned values are derived from the conservative values of the vertices that are directly affected by the injection positions. Alternatively, by using the hybrid suffix (see Quantitative CEL Functions in Ansys CFX in the CFX Reference Guide), these functions can use the values you specify at the injection positions.

If you are using shortcut menus to form CEL expressions, note that injection regions appear under Physics Locators > Other, not under 2D or 3D.

Injection regions are not compatible with:

  • Multi-phase flow

Other Limitations:

  • When the solver control advanced option of Surface Overlap Type is set to Mapped Faces (see Injection Control), injection positions must be geometrically separated enough to avoid having multiple injection positions directly influence the same mesh elements or vertices.

  • For transient blade row cases, hybrid solution values do not correctly show the influence of injection regions on boundary vertices that are directly influenced by any injection region. However, in all cases, conservative solution values are expected to be properly influenced by injection regions.

  • When using the Selected 2D Regions option, the mapping of the holes on the mesh assumes that, in the region of each hole, the mesh surface is approximately planar. Any significant variation of the mesh normal direction across a given hole cross-section can lead to inaccurate mapping.

  • Injection regions cannot be defined with a selected 2D region that has ‘thin’ mesh topology. In particular, the 2D region cannot contain a thin surface and cannot generally have two or more geometrically coincident faces.