ASME
ASME PTC 19.3 TW
Thermowells — Performance Test Code Supplement
The calculation standard for thermowell strength in flowing fluid, covering steady-state and dynamic stress and in particular the wake frequency problem, where vortices shed from the well excite it at its natural frequency and it fails by fatigue at the root. It is the reason a thermowell cannot simply be made longer for better immersion, and the reason a broken well recovered from a line is an engineering finding rather than a maintenance one. The 2010 edition replaced the older Murdock method and is less permissive.
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