Structural design of the Francis turbine rectangular draft tube with circular corners

[SD12]

Hello!

I am trying to figure out how to perform a structural analysis of the rectangular draft tube to a Francis turbine subjected to internal pressure.
I would like to know if there are any rules or codes or theory books that gives an introduction to this problem.
There are two issues:
- Calculate stress due to the internal pressure in such a rectangular pipe
- Calculate stress in "mitre bend" consisting of several rectangular segments.

I will greatly appreciate any input.

Best regards,
Sergey

 

[IdanPV]

Hello,

Does ASME certificate is required?

 

[SD12]

Hello.

No, I do not use the ASME code.
EN 13445-3 is preferable but it has no stress assesment procedure as far as I know.

 

[IdanPV]

Maybe part 15 of EN13445-3 will help?
I know it is not a vessel, but it might help you.

 

[SD12]

Yes, it probably will. But to asses the stresses in knuckles between the segments is the issue.

 

[IdanPV]

Does FEA is an option?
If so, you may want to consider it.