Parameter Z for fixed tubesheet - EN 13445

[Ehiman1]

Hello to everyone,
When you design a heat exchanger with fixed tubesheets in accordance with EN 13445 you can find a parameter Z:

Which is the correct value for this parameter?
I have channel flanged with tubesheet welded to the shell on each side.
Is it more correct to design with parameter Z near to 0 or 5?
A value of 0.52 is recommended for my software (it is only a note)

Thank you at all

 

[Ehiman1]

Anybody can help me please?

 

[SnTMan]

extragol1A, do you not calculate Z, based on the factors in the equation? Note I don't have a copy of EN 13445, and can't help you select said factors.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[Ehiman1]

My doubt is not about how can I calculate Z parameter! I would like to know if it is better to have this value near to 0 or 5. Is it better to have clamped tubesheet or simply supported when I have exchanger as described in my first post?

 

[SnTMan]

extragol1A, I have no idea how EN 13445 works, but under ASME Sec VIII, Div.1, Part UHX rules for heat exchanger tubesheets, considering a tubesheet as simply supported can exempt calculation of stresses in the intergal cylinder(s), but usually at the cost of a somewhat thicker tubesheet.

Depends on how you define "better" I suppose.

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[Ehiman1]

Many thanks for your answer!
I was wondering these questions because I have had doubts about the design an exchanger with a tube bundle with high stifness and shell with stifness close to 0. The calculation is ok, everything is verified, including tubesheet thickness.
It was my personal doubt only!

 

[r6155]

extragol1A. You need to read (slowly) the code in full before use the computer, and understand the restraint factor Z when Z is close to 0,52.
I feel you are some confused along your several post as civil/environmental. I suggest you contact a pressure vessel engineer

Regards

 

[Ehiman1]

Dear r6155,
I have read the code, with 0.52 you can have the minimum bending stress on the tubesheet, but my question was another one.
Civil/environmental is a setting I can t change from the beginning.
English is not my mother language, so I can explain me in the wrong way Sometimes, but for you,instead of write for nothing, shut up please, your answer is useless.

 

[r6155]

extragol1A. I am taking my time (like others) to help you (free), but you need to do a minimum effort to understand your problem before initiate a post.
Remember that code is for design, fabrication and inspection, not only calculations with computer.

Regards

 

[david339933]

but for you,instead of write for nothing, shut up please, your answer is useless.

Very nice....I wouldn't help you if you paid me.