Extract internal volume

[cowski]

A coworker needs to extract the internal volume of an assembly for a flow analysis (CFD). The only way I know is to:
1) export dumb solids to a file
2) unite relevant parts together
3) extract interior surfaces (extract region)
4) cap any holes (inlets/outlets)
5) sew surfaces into a solid
6) subtract any relevant parts out of the 'flow' solid

Anybody have a different and/or easier method?

I searched and found this thread: thread561-135984, but it is basically the same procedure as above.

 

[hudson888]

If you use such a procedure then during the extract region stage be sure to turn on "ignore holes" that will save you some time in capping openings.

There's always more than one way to kill a cat as the saying goes. You can occasionally model a solid from which to subtract the original so that you're left with the resultant cavity. There are so many ways to do this and variation of strategy to arrive at the desired geometry that I couldn't begin to describe them all, but NX is a very flexible tool and never more so that when dealing with these kinds of problems.

Lastly I'd have to add that if you're designing in the knowledge that you will need to analyse these aspects of the design then it may pay to design the cavity as a subtraction solid so that it may be used as to check the flow later on. Depending on your existing design a parametric construction may often be wound back to the point where useful elements of the cavity can more easily be extracted or linked at a timestamp for later analysis.

Best Regards

Hudson

www.jamb.com.au

Nil Desperandum illegitimi non carborundum

 

[Berserk]

Except for exporting dumb solids, I do the same thing for CFD of air induction systems.

I have seen some models were they have incorporated the need for internal volumes without ribs in the design so what they do is use subtract instead of shell or thicken.

They model the inside and use it to subtract from the actual body. Then they add the ribs.

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