Hoop stress calculation for a Oval shaped pipe 1

[chshbt]

Hi,

I'm designing a valve as per ASME Sec VIII div -1. To maximize the capacity I'm trying to make the inlet into Oval shape. But I'm not sure how to calculate the Hoop stress for a given internal pressure. Please see attached oval example.

Thank you in advance.

 

[C2it]

F.E.A.

 

[LittleInch]

I have to ask why you think this maximises the capacity? There's normally nothing better than a round hole for flow and I think if it was better, would be done more often by now, but maybe you have a particualr reason for this which would be interesting to see. Otherwise C2it is correct - FEA is the only way to analyse this.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[chshbt]

Hello LittleInch,

Please see attached file (this is the top view). Here the round inlet merges into the valve gallery. I want to merge the inlet smoothly into the gallery to minimize the flow losses. This merging is resulting in the oval cross section. I want calculate the wall thickness required at that region by calculation Hoop stress. But it seems I've to rely on FEA only.

Please let me know if know any other method.

Thank you

 

[corus]

Here's a link to a paper on the subject.

http://www.acwhyte.fsnet.co.uk/ovalpipepaper.htm

 

[JStephen]

If a section is symmetrical, you can split it in half, sum forces across the cross section, and find hoop stresses from that. The problem with the oval is that you'll have bending stresses that are not present in a cylinder, and you can't get them from that analysis. And, if it's a short section, you'll have bending stresses associated with the transitions to other shapes at the ends. FEA or possibly testing of a sample would be in order.