How can the number of tube-side passes be increased in a multi-pass heat exchanger?

• A. By Adding Divider Plates on Channel Heads
• B. By Increasing Tube Diameter
• C. By Reducing Shell Diameter
• D. By Reducing Flow Rate

Answer: (A)

The number of tube-side passes is determined by how the flow is routed through the tube bundle. Divider plates on the channel heads split the flow into multiple separate subchannels as it enters and exits the tube side. This creates additional flow paths that direct the fluid to traverse the tubes, reverse direction, and go through the bundle again in a controlled sequence. By carving these separate paths, you can increase how many times the fluid passes through the tubes before exiting, effectively raising the tube-side pass count.

Changing tube diameter or shell diameter alters geometry but doesn’t create new flow reversals through the tube bundle, and reducing the flow rate lowers velocity and pressure drop without increasing passes.