I am currently working on a project to replace a NET type heat exchanger. Why is pressure thrust from the expansion joint not considered when designing the floating head, tubesheet, or tubes?
Are you talking about an expansion joint in the shell or an expansion joint in the floating head cover assembly as would be required if you only had one tube pass?
In the head assembly, located between the floating head and the shell side head. Is it typical to add an external force to the floating for the bellow pressure thrust?
OP, the pressure thrust (which is axial) from the bellow will be considered in the design of the supports. Floating head, tubesheet, tubes all see the pressure differentials and will have no impact by the pressure thrust.