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-   -   Combustion in a sphere (http://www.cfd-online.com/Forums/cfx/18558-combustion-sphere.html)

Caz June 22, 2001 13:28

Combustion in a sphere
 
I am constructing a spherical vessel in which I will simulate combustion of methane and air (single phase). Ignition of the gas will be induced by raising the central spherical cell temperature to approx. 1100K.

So, my question is - can I use build where the north and south poles will cause possible problems for mesh analysis?

Do you know a way around these N & S poles occurring?

I am having major problems running meshbuild as it keeps crashing, and therefore prefer to use BUILD.

regards Caz

Robin Steed June 22, 2001 21:21

Re: Combustion in a sphere
 
Are you referring to CFX4-Build or CFX5-Build?

If you are referring to cfx5, you can reparameterize the surface with the following steps:

i) break the sphere into octants by selecting the surfaces and using the Edit > Surface > Break command.

ii) use Create > Surface > Composite, selecting one quadrant at a time.

The composite surface function can be used on one or more surfaces (in this case you want one) and creates new surface parameterization by rotating the view and projecting a regular grid pattern over the surface. The unstructured mesher will have no difficulty with this surfaces parameterization.

Upgrades in CFX-5.5 will make this much less problematic.

If you are using CFX-4, you will have to break your sphere into an O-grid (ie a square in the center with a block on each side expanding out to the surface.)

Robin


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