Page 24 - 2019

This research also presents standardization and optimum design approach of flange and
flued expansion bellow fulfilling ASME VIII-1 and TEMA standard requirement.
Methodology to define expansion bellow geometry is developed and geometry
dimensions are tabulated for expansion bellow diameter from 300 to 2000 mm and
thickness from 6 to 30 mm. This range covers thickness and diameter in which flange
and flued expansion bellows are generally used for shell and tube heat exchangers. Each
defined geometry is analyzed using finite element method and maximum von Mises
stresses are calculated for bellow axial displacement from 0.5 to 1.5 mm and internal
pressure from 0.1 to 6.5 MPa. Spring rate is also calculated for each defined geometry for
consideration in tubesheet calculation. This results in total 20 number of tables and
approx. 6804 number of analysis iteration to determine stresses and 2268 iteration to
determine spring rate with combination of various bellow geometry, design pressure,
bellow axial displacement and modulus of elasticity. Using standard defined geometry,
optimum design methodology is developed fulfilling ASME VIII-1 and TEMA
standard.Accordingly, optimum design methodology is developed, tested and compared
with existing design. With the case studies presented for cost saving, 14% reduction in
tubesheet & bellow weight was realized which results in reduction of cost of the
equipment. With the case studies presented for time saving, approx. 30 to 40 hours
saving per heat exchanger in finalization of heat exchanger design was realized with
standardization approach. Results depicted that proposed standardization approach and
design methodology will optimize expansion bellow and tubesheet thickness and will also
save considerable time in finalization of heat exchanger design.
Keywords: Flanged and flued expansion joint, expansion bellow, axial deflection, thick
wall expansion joint, spring rate, thermal stress, tubesheet, ASME VIII-1, TEMA.

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