USCG Exam PracticeThermodynamics and heat exchangers
In a shell-and-tube heat exchanger, what is the primary purpose of the baffles installed in the shell?
- A. To prevent the tube bundle from expanding and buckling under thermal stress.
- B. To separate the two fluid streams and prevent mixing.
- ✓ To direct the shell-side fluid back and forth across the tube bundle, raising velocity and turbulence.Correct
- D. To allow one tube sheet to float and accommodate thermal expansion.
Why C is correct
DOE-HDBK-1018 Vol.1 §2-1 states that baffles in the shell direct the shell-side fluid back and forth across the bundle to raise velocity and turbulence, thereby improving heat transfer. Thermal expansion accommodation is a function of the floating tube sheet or U-bend design, not the baffles.
Cited:DOE-HDBK-1018 Vol.1 §2-1