Study of Bolted Joint Integrity and Inter-Tube-Pass Leakage in U-Tube Heat Exchangers—Part I: Analysis

Abstract

“Three element bolted joints,” consisting of an unstayed tubesheet sandwiched between two tapered hub flanges, find extensive use in U-tube type heat exchangers. A comprehensive analysis technique is herein developed to investigate the structural characteristics of such joints. Design strategies to reduce stress levels in the tubesheet and the flanges are proposed. In particular, the concept of “controlled” metal-to-metal contact beyond the bolt circle between the mating surfaces is introduced and explored in depth. The solution is readily programmed on a digital computer for application in analysis oriented design evaluation and optimization studies.