Tubesheet calculation when NTIW is used (ASME interpretation) 1

[Peregrino7]

The general conditions of applicability for tubesheets of ASME Section VIII UHX-10(a) require the tubesheet be uniformly perforated over a nominally circular area.
The definition regarding "nominally circular area" has been a contentious issue on most shell and tube heat exchangers, as very few shell-and-tube layouts can be deemed to be "uniformly perforated over a nominally circular area".

Referring to ASME Interpretation VIII-1-04-61
Question: Do tubesheets for shell-and-tube heat exchangers having a no-tubes-in-window (NTIW) baffle design fall within the scope of Section VIII, Division 1 Part UHX?
Reply: No; see UHX-10(a) and U-2(g).


Since Part UHX provides no guidance for the design of tubesheets of an NTIW configuration - what is the accepted design basis used by COMPRESS?

 

[TJOrlowski]

Shell & Tube (and specifically tubesheets) seems to be the red-headed stepchild of most (if not all) commercially developed mechanical design software packages.

U-2(g) is the way to go here. Talk with your AI - he may accept designing the tubesheet(s) in accordance with TEMA, or require you to do FEA.

ASME had a tough time of it when they were initially developing their rules for the design of tubesheets: kept telling fabricators to use TEMA when the results were unreasonable. The TEMA calculations have been consistent, and reliable.

Using the TEMA method would be my first alternative if I couldn't perform the calcs and get a reasonable output using the ASME method(s).

-TJ Orlowski

 

[Bobfromoh]

I have a question. In the baffle detail section of the heat exchanger module, where it says "Each Baffle supports every tube", could this refer to NTIW baffle design?

 

[TJOrlowski]

Yes it could. It could also refer to full tube supports in the case of TEMA type "K" shells.

-TJ Orlowski