Analysis of stress types in heat exchangers with fixed tube sheets
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In a fixed-tube-sheet heat exchanger without expansion joints, under the pressure acting on the shell side, what types of stresses are present in the tubes regarding their axial stress, and in the shell cylinder regarding its axial stress? What types of failures are likely to occur?
The axial stress in the tube should be compressive, while the axial stress in the shell-side cylinder should be tensile. In the absence of expansion joints, the cylinder yields and suffers tensile failure.
Since the tube sheet deforms to both sides under the pressure from the shell side, shouldn’t the heat exchange tubes also be subjected to tensile force?
The heat exchange tube is subjected to the pressure in the shell side; due to the Poisson effect, it tends to elongate axially. However, this elongation is restricted by the tube sheet, so compressive stress is generated.
Will the pipe still be under compressive stress if an expansion joint is added?