Shell-and-tube heat exchanger design: which of the following baffle shapes is not a transverse baffle used to increase shell-side turbulence?
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ASegmental baffle
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BFlat plate extending across the shell
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CDisk type baffle
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DHelical type baffle
Answer
Correct Answer: Helical type baffle
Explanation
Introduction / Context:Baffles in shell-and-tube exchangers direct shell-side flow to enhance heat transfer and support tubes. Most common designs use transverse baffles that force crossflow across the tube bundle, raising turbulence and film coefficients. A contrasting family creates longitudinal flow with a helical path.
Given Data / Assumptions:
- Conventional single-shell-pass exchangers.
- Transverse baffles promote crossflow; longitudinal/helical promote helical/axial flow.
- Goal: identify the non-transverse option.
Concept / Approach:Segmental (single, double), disk-and-donut, and flat-plate baffles are classic transverse styles. They repeatedly redirect flow across the bundle. Helical baffles, by contrast, use a spiral baffle arrangement to guide near-plug, longitudinal flow with lower pressure drop and reduced fouling—these are not transverse baffles.
Step-by-Step Solution:List transverse types: segmental, flat plates, disk-type (disk-and-donut).Recognize helical design produces axial/helical channeling.Therefore, the non-transverse choice is the helical type baffle.
Verification / Alternative check:Vendor literature for helical-baffle exchangers highlights axial flow and lower shell-side pressure drop compared to segmental crossflow designs.
Why Other Options Are Wrong:Segmental / flat plate / disk type all interrupt flow transversely, promoting crossflow.
Common Pitfalls:Confusing “disk-type” with donut rings in disk-and-donut (still transverse overall); assuming helical equals segmental because of baffle count.
Final Answer:Helical type baffle