How best to create Mesh in Salome 9.12.0

Greetings. I have attempted to follow the Salome video tutorials offered e.g. “general ways of usage” and “meshing the bracket” in the creation of a mesh for a centrifugal fan created in Rhino 7 as a 3dm file in inches, converting inches to units in Meters, then saved as a STEP file using Rhino’s default options, and imported into the Salome Geometry Module.
After multiple attempts and failures at creating a mesh for use in OpenFOAM, I wondered if I would have better luck with a closed solid polysurface rather than separate closed solid polysurfaces of rim, an array of blades, and shroud,
I performed Boolean union operations on the fan rim and blades, then added the fan shroud, producing a one-piece closed solid polysurface.
The inner diameter is 11 inch, or 280 mm, outer diameter is 12 inch, or 305 mm. The fan blades are constant-chord tapered tip modified NACA 2412 airfoil having a leading edge length of 1.4 inch, or 36 mm, and a trailing edge length of 1 inch, or 25 mm
I’ve tried using NETGEN 1D-2D-3D, Hexahedron and Body Fitting Algorithms.

Upon clicking Compute Mesh, sometimes the attempt fails immediately, other times it computes for hours and hangs at 99% ultimately to be cancelled.
Any suggestions?
Thanks in advance.

hexahedron does not work like that, you need to decompose your geometry into blocks, similar to blockmesh, so normal that it fails.
body fitting I don’t have a lot of experience, but in principle it is similar to snappy so it depends a lot in your background mesh (its parameters)
netgen, that I think is where you get in the 99% stuck, you probably have really small edge, in your step file, and that’s where netgen takes way too much time as it depends on the size of the edges, and as you have a reaaaally small edge it will take really small dimensions. try, netgen 3D + netgen 2D + wire discretisation with minimum length size, this will give you a better solution I think.
you can also use salome in convination with SHM have a look at this tutorial
also for the small edges, check in geom/repaire/geometry check (I am saying the name out of my memory could be different) it might tell you that you have some problems on it.
hope it helps.

@franco.ota Thank you so much! Here’s how I proceeded:

  • Regenerated the rim, blades, and shroud in Rhino and called the Quad Remesh
    command in Rhino on each object and saved as .STL, taking all default options.
  • Imported .STL file into Geometry module (took a while)
  • Activated Mesh module
  • Mesh>Create Mesh
  • Chose a Quad Algorithm
  • Clicked on Compute
    It’s running up the nodes and elements. Glad I’ve got 32 GB RAM and made room on my HD
    Thank you again!

Several errors, stl is not supposed to be used with a quad mesh only tri. Also rhino can produce step files use that. Also quad meshing is used mostly for structured meshing so a lot of work is needed it is not a “I throw you my geometry you do all the work” thingy. I would recommend to go with a text mesh with netgen instead.

@franco.ota Thank you. I couldn’t find a text mesh option but followed, as my version allowed, the steps in the general ways of usage video tutorial.

I really appreciate the help.

I meant a tet (tetrahedral) mesh the corrector from the phone change it. Well glad it is working.

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