I’ve been working on a shell and tube heat exchanger design for a university project and decided to put some thoughts down about baffles. I find the mechanisms behind heat exchangers quite interesting, so I might flow this up with a future post on heat exchanger design.
The baffles provide two main functions: they support the tubes and increase the heat transfer coefficient. Supporting the tubes reduces flow induced vibrations that are caused by eddies, it also helps in the positioning of the tubes when assembling and aids in maintenance when removing the tube bundles. The secondary objective of baffles is to increase the heat transfer coefficient. This is achieved by two mechanisms: increase in the cross flow velocity by guiding flow back and forth over the tubes, and by inducing turbulence through directed flow at these greater velocities.