### 10.6.6. Export to ANSYS TurboGrid

Native BladeEditor blades (blades that were produced by the Blade or Splitter feature without subsequent modification) can be sent to TurboGrid (via a cell connection) without an ExportPoints feature.

Note: If a geometry that is to be exported to TurboGrid fits within a cube of edge length 10 cm, the DesignModeler session unit (see Units Menu in the ANSYS DesignModeler User's Guide) should be set to Micrometer for better geometry precision.

An ExportPoints feature is needed to send the BladeEditor/DesignModeler geometry to TurboGrid (so that you can use TurboGrid to generate a mesh suitable for CFD analysis) only if the blades were:

- Modified using DesignModeler features (for example, to apply fillets, blends, and revolved cuts)

- Made using Airfoil design mode.

- Imported directly from external CAD.

Note: The ExportPoints feature generates blade profile data consisting of point coordinates. The resulting geometry in TurboGrid is an approximation of the BladeEditor/DesignModeler geometry. The ExportPoints feature should therefore not be used unless it is required.

The remainder of this section describes the ExportPoints feature and its use.

To start creating an ExportPoints feature, click the icon.

The feature properties are listed below:

Table 10.8: Details View for the ExportPoints feature: Export to ANSYS TurboGrid

Details of [Feature Name]
Export Points | [Feature Name]
Export Type | [Meanline | TurboGrid]
Export to file | [Yes | No] Export the profile data to files if you want to use the data in an external application (including ANSYS TurboGrid running in standalone mode or batch mode).
(If “Export to file” = “Yes”) File Folder | [Folder name]
(If “Export to file” = “Yes”) File Prefix | [Filename prefix]
Blade or Flow Path | [FlowPath or Blade feature selection] If you select a Blade feature then BladeEditor will attempt to select the pressure side, suction side, leading edge, and trailing edge surfaces of the blade. If it does not do this automatically, or if you select a FlowPath feature, then you must manually select the blade surfaces from which to extract the blade profile data. To do this, click the cell next to Blade Surfaces and then select the surfaces of the blade; these surfaces must collectively cover the entire blade surface except for the hub-facing and shroud-facing surfaces.
Blade Info From | [Blade | User Specified] This will be set to “User Specified” if “Blade or Flow Path” is set to the name of a FlowPath feature (as opposed to a Blade feature).
(If “Blade Info From” = “User Specified”) Number of Blades | [Value>1]
(If “Blade Info From” = “User Specified”) Blade Row Number | [Int Value]
Blade Surfaces | [Named Selection for blade surfaces]
Hub/Shroud Offset % | [0<Value<100]
Point Tolerance | [Value>0]
Export Shroud Tip | [Yes | No]
Output Layers: [a]
Output Layer 1? | [Yes | No]
Output Layer 2? | [Yes | No]
Output Layer 3? | [Yes | No]
[a] Layer items are listed for all layers defined in the FlowPath. Specify which layers are to be used in generating the blade profile data.

Note that a Blade or Flow Path feature must be specified. If you have imported (rather than loaded) a BladeGen file then there might not be a Blade or FlowPath feature available. In this case, you could create a FlowPath feature manually, or load (rather than import) a BladeGen file.

After this feature has been generated, and when it is selected, the exported profiles appear in the 3D viewer.

After this feature has been generated, you can link the Geometry cell to the Turbo Mesh cell of a TurboGrid system.

The blade profile (point) data is automatically extracted from the blade solid model at the eligible specified output layers by slicing the blade surfaces to give profile (intersection) curves. The profile curves are then tessellated into piecewise linear segments using the Point Tolerance value. This value defines the maximum deviation (in model units) between the piecewise linear curve and the profile curve. The piecewise linear curve points are output to TurboGrid or to the specified output file.

Regarding layer eligibility (for use in creating profiles for output) and the use of blade tips and hub/shroud cuts:

- If you select a Blade feature and it has a shroud tip, the eligible layers exclude any layers past the shroud tip; layers lying on or above the shroud tip will not be used to generate profiles for export.

  The export of the tip profile itself can be controlled with the “Export Shroud Tip” option of the ExportPoints feature.

  Tip clearance settings have no effect on the exported hub and shroud curves.

- If the FlowPath (that is selected directly or that is associated with the selected Blade) has a hub and/or shroud cut applied, the eligible layers exclude any layers past the cut(s); layers lying on or below the hub cut, or on or above the shroud cut, will not be used to generate profiles for export.

  If the FlowPath has a hub and/or shroud cut applied, then the hub and shroud curves that are exported will be those used to define the cut.

  Because profiles are not exported for the Hub Cut or Shroud Cut layers, if the Hub Cut or Shroud Cut is an existing FlowPath layer, this layer will not be exported. The workaround is to ensure that the FlowPath layer that neighbors the Hub Cut layer or Shroud Cut layer is sufficiently close to the Hub Cut layer or Shroud Cut layer that TurboGrid can recreate the blade surface.

Selecting ineligible layers will result in a warning message associated with the ExportPoints feature.

By default, the profiles are extracted from all eligible layers defined in the applicable FlowPath: the specified FlowPath feature or, if a Blade feature is specified, its parent FlowPath feature.

If output is specified on the hub and/or shroud layers (these layers are in the FlowPath feature by default), then a small offset, 'Hub/Shroud Offset %', is required in order to guarantee a complete intersection of the layer with the blade; such an offset is applied by default. The offset applies inwards in the spanwise direction. The offset only affects the location where the point data is extracted from the blade; it does not cause the blade profile at the hub or shroud to be applied at the offset location.

Care must be taken to ensure that sufficient output layers are used when exporting so that the TurboGrid blade surface is a reasonable approximation of the BladeEditor solid model. Note that using many output layers with a small point tolerance can cause Bspline surface lofting problems in TurboGrid. In these cases, you may need to override the Blade Geometric Representation in TurboGrid and change the Curve and Surface Types to 'Piece-wise linear' and 'Ruled', respectively.

You will need to use one ExportPoints feature for each blade that you want to export, even if they are in the same blade row. For example, if you have a main blade and a splitter, you will need to create two ExportPoints features and select the appropriate blade surfaces for each feature.

You specify which exported blade(s) to load into TurboGrid by editing the Turbo Mesh cell properties. See Table 11.1: TurboGrid Turbo Mesh Cell Properties for more information.

Because the blade profile data is extracted from the blade surfaces, the ExportPoints feature can also be used to extract blade profile data from an imported CAD model. The only requirement is that a FlowPath feature must be defined to specify the output layers. If you specify a FlowPath as the Blade or Flow Path property, you will need to specify the number of blades and the blade row number. The blade row number lets TurboGrid know how the exported blades are ordered, and whether any exported blades are part of the same blade row. The blade rows are sorted in ascending order from inlet to outlet.

Release 18.2 - © ANSYS, Inc. All rights reserved.