A New Type Of Baffle For Shell-and-tube Heat Exchanger——the Alternating Inclined Baffle

The heat exchanger is a key piece of equipment in many industries such as power generation, food processing, and oil refining. Among them, the shell-and-tube heat exchanger is the most commonly used type, accounting for over 40% of applications. Shell-and-tube heat exchangers have various types of baffles, among which the single segmental baffle is widely adopted due to its low manufacturing cost, high heat transfer rate, and ease of installation. However, the single segmental baffle often suffers from high pressure drop and severe vibration due to the presence of dead zones, leading to reduced heat transfer efficiency, particularly in cooling applications requiring high pressure.

To improve the efficiency of shell-and-tube heat exchangers, various methods have been proposed, many of which involve the use of longitudinal helical baffles to reduce flow stagnation caused by baffles.

The use of helical baffles is one such alternative and the most commonly employed method, as helical baffles can generate greater flow turbulence, thereby reducing pressure drop and increasing heat transfer rates. Further studies have shown that a helical angle of 40° yields the optimal thermal-hydraulic performance. However, the manufacturing cost of such baffle designs is significantly higher than that of traditional single segmental baffles, which poses a major challenge for adoption across many industries.

The following diagram illustrates three different types of baffles:

a) Single segmental baffle

b) Helical baffle

c) Alternating inclined baffle

The pair of baffles in the alternating inclined baffle design is shown below:

Under identical hydraulic boundary conditions, the performance of the new structure was evaluated and compared with single segmental and helical heat exchangers. The following conclusions were drawn:

The results indicate that the alternating inclined baffle structure is an effective method for improving heat exchanger efficiency, as it retains the advantages of helical baffle designs while significantly reducing design and manufacturing complexity. Although currently limited to theoretical evaluation, the new baffle design demonstrates good compatibility and scalability due to its partial similarity to the single segmental baffle. Further optimization of the geometry, practical considerations for structural stability, and maintenance of the alternating inclined baffle structure will be key areas for future research.