Engineers at Solutia (St. Louis) had a dilemma: how to prove that a proprietary flow distributor would outperform and save money over a baffle in the design of a shell-and-tube heat exchanger, and how to communicate these results with a nontechnical audience.
While heat exchanger design typically focuses on surface area requirements, the fluid flow patterns within the tubes can be of equal importance. One optimization target is the equal distribution of flow into each tube within the bundle; in an unmodified heat exchanger, this rarely happens. Rather, the tubes in the middle of the bundle receive the bulk of the fluid because of inlet fluid impingement. The tubes on the side of the bundle get the fluid that works its way over. This tube-side flow maldistribution produces a condition in which much of the heat transfer surface area is wasted. Consequently larger, more costly heat exchangers are used to meet the original design specifications.