(Morrigan, as a synonym of Morgan of Arthurian legend)

Tuesday, 18 August 2009

Throttle body calcs-4

This is a second attempt at creating a fluent analysis of a throttle body, this time utilising MSC Patran to produce the volume mesh. I now believe that for straight forward meshes that Patran has greater capability than GAMBIT.

Second attempt throttle body - Rhino3D

The throttle body model was generated in sections, this will allow quick production of the varying throttle angle models to be run through. That is once i work out what i am going to be looking for.

Throttle volume meshed in Patran

Meshing coincident volumes in Patran, when you have more than six sides requires a little ingenuity. Because the software cannot recognise that the faces of the volume parts meet, it will not produce the same mesh on both. Therefore you have to create a surface mesh on one face. Mesh the volume, then disassociate it and associate it with the adjoining face, before meshing the adjoining volume. In this way you can create matching volume faces which will equivalence into a larger volume. In this way the model is split into a top section of the air horn, then throttle butterfly, then a profile change from circular to oval, and the final section for mounting the fuel injector.

Spliting / Guiding surfaces for volumes

This allows great control of the meshing process. GAMBIT will now only be used for applying the face properties to the finished volumes. Only TET4 meshes are able to be read from a patran neutral '.out' file, into GAMBIT.

Mesh in Fluent

The Fluent run is progressing smoothly, with a steady reduction of continuity residuals. And the results are in...
Fluent output

Fluent output - looking down the bore, (vortices rather like an owl)

Fluent output

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