Hello all,

I hope someone can advise on the requirement for the use of a bellow in a heat exchanger. I've come across on several occasion on a fixed tubesheet heat exchanger design but not sure what is the governing factor or when is it required to use a bellow.
I notice towards the end of the tubesheet analysis there's a 'Max axial differential thermal expansion' result whereby it states the movement/growth, but at what point does it really need a bellow? Also there's an 'Allowable load on the Tube/Tubesheet Joint' & 'Actual loading' calculation, does this have any correlation with the movement/growth result?
Appreciate all reply.

Thanks.