10.4.3. Transferring Blades from Ansys BladeGen

BladeEditor provides a geometry connection between BladeGen and DesignModeler. Reasons for importing BladeGen blades into DesignModeler include:

  • BladeGen can output geometry in many different point data formats, but its surface output in IGES format is cumbersome to use.

  • BladeGen does not produce a solid model in a standardized format such as Parasolid.

  • You can combine an imported blade with other CAD geometry imported via one of the many DesignModeler-supported CAD file formats.

  • You can add hub and shroud fillets.

Through BladeEditor, one or more BladeGen models can be linked into a DesignModeler session, so that any changes to the BladeGen models will be reflected in DesignModeler the next time you update the Geometry cell.

When you import a BladeGen model, BladeEditor does the following:

  • Constructs blade surfaces

  • Creates a solid model for the blades and hub

  • Creates 2D sketches for the meridional contours and non-flow-path hub geometry

  • Creates periodic fluid zones

The preferred method of importing a BladeGen file is to create a link from a BladeGen system’s Blade Design cell to a Geometry system’s Geometry cell (representing DesignModeler/BladeEditor).

This link maintains the data transfer relationship between the two cells. The desired import options should be specified in the Blade Design cell properties (see Table 9.2: BladeGen Blade Design Cell Properties). Note that the link can transfer geometry with either the Load NDF or the Import BGD data transfer type, as specified in the Blade Design cell properties. After you make the link, the Geometry cell should be updated to process the imported geometry.

Note:  If you edit the Geometry cell before updating it, then the ImportBGD feature details that are shown in BladeEditor may not accurately reflect the Blade Design cell properties. To refresh the ImportBGD feature properties, click   in BladeEditor. It is not recommended that you edit the ImportBGD properties inside BladeEditor because they will be overwritten by the properties from the Blade Design cell the next time you update the Geometry cell.

The following topics are discussed:

 

10.4.3.1. Load NDF Data Transfer

As mentioned earlier, a link from a Blade Design cell to a Geometry cell can transfer BladeGen geometry to BladeEditor with the Load NDF data transfer type.

The Load NDF data transfer type uses the Neutral Data Format to pass the blade design details from BladeGen to BladeEditor.

The advantage of using the Load NDF data transfer type is that BladeEditor creates native blade geometry features that can be modified.

The disadvantage of using the Load NDF data transfer type is that the model features are limited to those available in BladeEditor. Consequently, some of the advanced features available in BladeGen cannot be used with this approach. For details of the restricted features, see Neutral Data File (NDF File) in the TurboSystem User's Guide.

Note:  When updating the geometry from BladeGen, any changes to the following BladeEditor features are not preserved:

  • Sketch parameters

  • Angle/thickness curve points

 

10.4.3.2. Import BGD Data Transfer

As mentioned earlier, a link from a Blade Design cell to a Geometry cell can transfer BladeGen geometry to BladeEditor with the Import BGD data transfer type.

An alternative way to import BladeGen geometry into BladeEditor is to import a BladeGen file from outside the project. To do this, click   in the BladeEditor toolbar. When you click this icon, you will be prompted for the location and name of the BladeGen (.bgd) file. Once the filename is selected, the details view enables you to select the properties for the import. These properties are listed in Table 10.4: Properties for the ImportBGD Feature. As with other DesignModeler feature properties, you can double-click in a property value box to change the selection to the next choice, or single-click the property and select the value from the drop-down list.

Table 10.4: Properties for the ImportBGD Feature

PropertyDefault ValueFunction

ImportBGD

ImportBGD#

This property defines the name of the import feature.

Source

(selected BGD File)

This property defines the name and path of the imported .bgd file. You can change the source to a new .bgd file if Refresh is set to Yes.

Unit Preference

(default is the DesignModeler length unit)

You may change the value of this property to the intended BladeGen model length unit if the latter does not match the DesignModeler length unit. If the BladeGen model length unit is specified as "Unknown" (in the BladeGen model properties), then BladeEditor will interpret the model as having the length unit specified here, and will process the model by converting from this unit into the DesignModeler length unit. Otherwise, the unit specified here will be ignored, and the model will be converted from the unit specified in the .bgd file into the DesignModeler length unit. It is recommended that you specify a length unit in BladeGen so that this information is stored in the .bgd file.

Make sure that the length unit specified here is appropriate for the model. If the BladeGen dimensions are too small, DesignModeler may fail to import the BladeGen model.

Create Hub

Yes

If this property is set to Yes, then BladeEditor will create a HubProfile sketch for the non-flow path hub geometry, and will create a revolved body feature called HubBody.

Hub Offset

1 (Inch)

This property defines the default line offset (in the preferred length unit) for creating the initial HubProfile sketch.

Note that this property is available only if Create Hub is set to Yes.

Create Blades

All

If this property is set to All, then BladeEditor will create all the blades using the number of blades specified in the BladeGen model.

If this property is set to 1, then only the first blade will be created.

Merge Blade Topology

Yes

If this property is set to No, then BladeEditor will create the blade with four faces corresponding to the leading edge, pressure side, trailing edge and suction side. This can make it easier to create a structural mesh for the blades in the Mechanical application.

If this property is set to Yes, then the blade faces will be merged where they are tangent to one another.

Blade Loft Direction

Streamwise

If this property is set to Streamwise, then BladeEditor will loft the blade surfaces in the streamwise direction through curves that run from hub to shroud. This is the default because the surface is more well defined, especially for flank-milled blades.

If this property is set to Spanwise, then BladeEditor will loft the blade surfaces in the spanwise direction through the blade profile curves.

For an illustration of these lofting methods, see the figure after this table.

Create Shroud Clearance

No

This property specifies whether a shroud clearance is created. If No is selected, then no shroud clearance is created. To create a shroud clearance, choose either Relative Layer or Absolute Layer. The blade(s) will be trimmed off at the selected BladeGen output layer, and the layer contour will be created in the LayerProfile sketch.

If Relative Layer is selected, then the selected Layer Number is relative to the shroud layer, for example, 1 implies the first layer closest to the shroud layer, 2 implies the second closest layer to the shroud, etc.

If Absolute Layer is selected, then the selected layer index counts up from the hub layer, which is zero.

Layer Number

1

This property defines the selected layer index for the shroud clearance.

Note that this property is available only if Create Shroud Clearance is selected.

Create Fluid Zone

Yes

If this property is set to Yes, then BladeEditor will create a StageFluidZone body for the flow passage, and an Enclosure feature to subtract the blade body. The resulting Enclosure can be used for a CFD analysis of the blade passage.

Create Named Selections

Yes

If this property is set to Yes, then BladeEditor will create NamedSelections (regions) for the typical faces of the blade passage, that is, Blade, Hub, Shroud, Inflow, Outflow, PeriodicA and PeriodicB. These NamedSelections can be used as selection groups in other Ansys Workbench applications.

Note that this property is available only if Create Fluid Zone is set to Yes.

Blade Extension (%)

2

This property defines the surface extension length (as a percentage of the average hub to shroud distance) for the blade surfaces. These surfaces are extended and then trimmed to the MasterProfile sketch to ensure that the blade solid correctly matches the hub and shroud contours.

Periodic Surf Extension (%)

5

This property defines the surface extension length (as a percentage of the average hub to shroud distance) for the periodic surfaces. These surfaces are extended to ensure that the StageFluidZone is properly cut.

Periodic Surf Style

Three Pieces

This property specifies the style of the periodic interface surfaces.

If Three Pieces is selected, then the periodic surface is created in three connected pieces: one upstream of the blade, one within the passage, and one downstream of the blade. This style can better accommodate highly curved or twisted blades, and is similar to the Ansys TurboGrid style of periodic surface.

If One Piece is selected, then the periodic surface is created as a single surface.

Note that this property is available only if Create Fluid Zone is set to Yes.

Refresh

Yes

This property specifies whether the imported BladeGen model should remain linked to the DesignModeler session. If this property is set to Yes, then when the DesignModeler Generate button is clicked, BladeEditor will check to see if the BladeGen file has changed. If the BladeGen file has been modified, BladeEditor will reload the file. If the BladeGen file has moved or has been deleted, BladeEditor will switch this property to No and will leave the blade geometry unchanged.

If this property is set to No, then BladeEditor will not reload the BladeGen file when the DesignModeler model is regenerated.


Figure 10.15: Spanwise Lofting versus Streamwise Lofting shows how spanwise lofting and streamwise lofting differ.

Figure 10.15: Spanwise Lofting versus Streamwise Lofting

Spanwise Lofting versus Streamwise Lofting

Once the properties for the ImportBGD feature have been set, click the Generate button, and the BladeGen model will be imported.

The following features will then be created in the tree view:

  • MerPlane: this plane is a copy of the Z-X plane; it is the plane on which the blade design sketches are created.

    • MasterProfile: a sketch defining the hub, shroud, leading edge, trailing edge, inflow and outflow boundaries of the blade passage (imported from the .bgd file) will be created. This sketch is used during the creation of the blade bodies, and can be used to create the fluid zone. You should not modify this sketch.[1]

    • BladeProfile: a sketch defining the locations of the leading and trailing edges for the main blade will be created.

    • HubProfile: a sketch defining the hub body will be (optionally) created. This sketch can be modified; however, you should take care to ensure that the sketch loop remains intact or the hub body will fail to regenerate.

      HubBody - (Optionally) the HubProfile sketch is revolved to create the HubBody feature in the tree view.

  • BladeBody - The blade surface data is imported and lofted in DesignModeler to create the BladeBody feature in the tree view.

  • StageFluidZone - (Optionally) the MasterProfile sketch is revolved and cut into a sector by the periodic surface to form the StageFluidZone body. This feature forms a sector of the fluid volume around a single blade, but the blade has not been removed from the volume.

  • Enclosure - When the StageFluidZone is created, the blade (and any other connected geometry) is removed from the StageFluidZone body by the Enclosure feature.

  • Named Selections - These are the labeled regions on the final Enclosure body: Blade, Hub, Shroud, Inflow, Outflow, PeriodicA and PeriodicB.

 
10.4.3.2.1. Limitations of the ImportBGD Feature

There is a known limitation with the ImportBGD feature when importing multiple BladeGen files. If you have imported two or more BladeGen files using separate ImportBGD features, and have turned on shroud clearance for one of these features, then the import process may fail. The workaround is to import the case(s) with shroud clearance first, then import the others.

Furthermore, changing the Blade Design cell Shroud Clearance property from "Relative Layer" or "Absolute Layer" to "None" will have no effect on the ImportBGD feature. In this case, you must change the Shroud Clearance property directly in the ImportBGD feature.

The following BladeGen model features are incompatible with BladeEditor, and prevent successfully importing a BladeGen case into BladeEditor.

  • trim profile


[1] This constraint is to prevent the MasterProfile and the blades from becoming inconsistent, because the blade surface data comes from BladeGen.