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Spurious geometry appears in Meshing after using “pull” command in SpaceClaim

    • FlorDeLis
      Subscriber

      Good day to you all

      I have a fluid body (extension at the outlet of a centrifugal compressor's diffuser).

      Due to recirculation at the outlet of the extension, I am attempting to extend the fluid body using the "pull" command in SpaceClaim.

      After changing the radius from 200mm to 750mm, the "pull" operation succeeds and the geometry appears fine in SpaceClaim. However, when I open meshing, the faces that form the top and bottom "walls" of the extension appear to span beyond the edges of the fluid body. Interestingly, if I export the geometry from SpaceClaim in .stp format, the faces are the correct size.

      The images below show the original fluid body, the extended fluid body with "overhanging" faces, and the extended fluid body wireframe. I hope this is sufficiently illustrative.

    • Keyur Kanade
      Ansys Employee
      Please check geometry in SpaceClaim.
      Select geometry in structure tree --> Use right click --> Select Check Geometry. (Or Tools - Fault Detection in DM)
      The geometry should be error free to proceed.
      If geometry has any errors, please modify/recreate geometry at those places.
      Plus SpaceClaim works on ACIS kernel and Meshing has geometry representation with b-rep. So there is geometry conversion and this may happen. If you can get setp file, you can import in SpaceClaim and continue.
      Regards Keyur
      How to access Ansys Online Help Document
      Guidelines on the Student Community

    • FlorDeLis
      Subscriber
      Hi Keyur
      Thank you for responding.
      I have done a check on the geometry in SpaceClaim as you describe. I've also invoked the various tools in the "Repair" tab in SpaceClaim. No errors are found in the model.
      The overhanging faces only appear in Meshing when the geometry is selected in the tree view. When the mesh itself is selected, the faces are not present (see image below). This leads me to think that the overhangs are a rendering artifact and not a genuine error in the geometry. I am thinking that this might have something to do with the geometry conversion that you mention.
      The smaller cylindrical surface on the geometry is split into smaller surfaces, which I achieved using the "shared topology" functionality. This is to create a mesh that is conformal with the mesh for the impeller of the compressor. Because of this, I would like to avoid converting the geometry to .stp file.
      The meshing eventually succeeds - I think that the long calculation time is due to the small maximum cell size I had specified. I am currently running a CFX case using the mesh shown above, but the appearance of the overhanging faces has shaken my confidence.
      Bemused but appreciative FlorDeLis
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