Page 23 - 2019

Ph.D.
(Engineering & Technology)
DESIGN AND OPTIMIZATION OF THICK WALL EXPANSION
BELLOW FOR FIXED TUBESHEET HEAT EXCHANGER

Ph.D. Scholar : Chikhaliya Kamlesh M.
Research Supervisor : Dr. Bhavesh P. Patel

Regi. No.: 15146051002
Abstract :
Flanged and Fluid type expansion joint (thick wall expansion bellow) used as an integral
part of many shell and tube heat exchanger where process conditions produce
differential expansion between shell and tubes. It provides flexibility for thermal
expansion and function as a pressure retaining part. Design of expansion joints are
usually based on trial and error method in which initial geometry must be assumed and
accordingly maximum stresses and spring rate is to be calculated. Inadequate selection
of geometry leads to have higher tubesheet and bellow thickness which increases cost of
equipment.

Classical plate and beam theory used by Kopp and Sayre for design of flexible elements
does not predict a state of stress at the knuckles or corners of the flexible element and no
reliable analytical method to evaluate stress at the knuckle and knuckle to annular plate
junction exists.These limitations not only result in an incomplete analysis, but also result
in overestimated stresses at the knuckle to annular plate discontinuity. This results in
increased thickness, thus stiffness of the flexible element, which counteracts the
expansion bellow purpose.

In present research work, design methodology of flangedandflued types (thick wall) and
thin wall expansion bellow available in various international codes and standards
including AD 2000, ASME BPVC, Section VIII-1 and Div-2, EJMA, EN 13445-3, EN 14917,
TEMA, GOST 30780, GB 16749, IS:19647 and BS-5500 is studied to understand latest
industrial practices. These codes and standards are compared in terms of information
available for thick wall expansion bellows design with regards to condition of applicability
of design formula, spring rate determination, parameter to define the initial geometry,
stress determination and fatigue evaluation. Inherent limitations of these codes with
respect to expansion bellows design, research gape and recommendations for effective
design are also presented.

To simplify design of tubesheet and expansion bellow,work flow is described fulfilling
ASME VIII-1 and TEMA requirement. Accordingly, methodology to decide requirement of
expansion bellow considering various design parameters is also developed.

04