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Julian September 22, 2005 12:54

CFX-mesh for a long pipe
I am investigating the potential for CFX to model a variety of multiphase flows and have more familiarity with cfx-mesh than I do with ICEM. The problem is this:

The pipe is 10m long and 0.08m diameter. I can easily mesh the ends of the pipe extrude the mesh axially to give cells that are aligned in the direction of flow. However, my version of CFX (currently 5.7.1) will only allow me to extrude up to 100 layers maximum. This means that my cells are 0.1m long, which is fine for stratified flow, but no good for slug or bubbly flow.

Is there a user variable that I can tweak to allow me to have more cells in the axial direction, i.e. can I override the default setting for the number of layers?

Glenn Horrocks September 22, 2005 19:30

Re: CFX-mesh for a long pipe

Can you extrude in two or more sub-sections and join them up? Also you might consider a structured mesh with ICEM-hexa.

Regards, Glenn Horrocks

Julian September 26, 2005 04:10

Re: CFX-mesh for a long pipe
Yes the extrude in sections and then join up is an option, though one that will probably leave me with unmatched boundaries every metre (though that itself will be an interesting test.)

As I said initially, I am not that familiar with ICEM and the battle that it will be to get the program to work just for a pipe is not on that I look forward to, though it is starting to appear that it might be the only way out.

Thanks for the coments, Julian

Glenn Horrocks September 26, 2005 23:23

Re: CFX-mesh for a long pipe

Don't forget you can rotate, scale, stretch and copy meshed items in CFX-Pre. That means you might be able to assemble your pipe geoemtry from smaller bits. If you extrude and sweep each bit from the same cross section mesh then the mesh will match up between segments and you will not need unmatched boundaries. Even though your mesh is composed of smaller mesh fragments they will still be one domain with no interfaces.

Regards, Glenn Horrocks

Julian September 27, 2005 04:19

Re: CFX-mesh for a long pipe
Thanks, I didn't know that. Julian

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