No Tube In Window (NTIW) Tubesheet Design
No Tube In Window (NTIW) Tubesheet Design
(OP)
Both TEMA and UHX do not cover the design of a NTIW tubesheet.
How are these tubesheets normally designed?
Is FEA the only solution?
How are these tubesheets normally designed?
Is FEA the only solution?





RE: No Tube In Window (NTIW) Tubesheet Design
Regards,
Mike
RE: No Tube In Window (NTIW) Tubesheet Design
I too agree with what you say
RE: No Tube In Window (NTIW) Tubesheet Design
As for FEA, it is not necessarily more accurate, and you can bet the customers don't want to pay for it.
Regards,
Mike
RE: No Tube In Window (NTIW) Tubesheet Design
Were is it used?....Thanks
RE: No Tube In Window (NTIW) Tubesheet Design
Regards,
Mike
RE: No Tube In Window (NTIW) Tubesheet Design
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Regards,
Mike
RE: No Tube In Window (NTIW) Tubesheet Design
Both TEMA and UHX do not let you credit plate thickness for the area that is not been drilled.
On the other hand,
as a significant area of your tubesheet is unsupported, you should be aware about the possibility of falling into UG-93 (d)(3) examination requirement:
"When a pressure part is to be welded to a flat plate thicker than ½" to form a corner joint under the provision of UW-13 (e), the weld joint preparation in the flat plate shall be examined before welding as specified in (d)(4) below…. The requirements of this paragraph shall not be apply to those joints when 80% or more of the pressure load is carried by tubes, stays, or braces".
RE: No Tube In Window (NTIW) Tubesheet Design
Regards,
Mike
RE: No Tube In Window (NTIW) Tubesheet Design
RE: No Tube In Window (NTIW) Tubesheet Design
Hopefully this would be available in the next TEMA update.
RE: No Tube In Window (NTIW) Tubesheet Design
UHX does in fact take into account untubed areas. It is considered in the effective tube pitch but limited to 4 times the product of equivalent diameter and tube pitch. I have not seen it make a big difference but it does have an impact.
EJL
RE: No Tube In Window (NTIW) Tubesheet Design
Regards,
Mike
RE: No Tube In Window (NTIW) Tubesheet Design
I was not trying to imply that UHX was applicable. In fact, I could probably make a convincing argument that UHX is not applicable in all but a few cases. The advantage that UHX has is that the background is widely available.
An assumption that I have seen several times on the NTIW design is to consider that the area is in fact tubed. In the case of UHX this area is considered to have a lesser strength because of the tube holes. These holes do not exist in the as-built exchanger. I cannot say if this assumption is more or less conservative, just that it was used more than once.
EJL
RE: No Tube In Window (NTIW) Tubesheet Design
I do know the work still has to get done:)
Mike