Shell-and-tube heat exchanger design: which of the following baffle shapes is not a transverse baffle used to increase shell-side turbulence?

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