How many arrangements are there for heat exchanger tube bundles?

Thread Content

How many arrangements are there for heat exchanger tube bundles? There are four arrangements of tubes in the tube bundle: equilateral triangle, square, square with 45° offset, and concentric circular arrangement, as shown in Figure 6-4. There are also corner triangles, etc. (a) Equilateral triangle arrangement; (b) Square in series; (c) Square in staggered arrangement; (d) Circular arrangement. Figure 6-4 shows the various arrangements of heat exchanger tubes. The equilateral triangle arrangement is the most common one, with equal spacing between the tubes. The greatest number of tubes can be arranged within a given tube sheet area, and marking and drilling are straightforward; however, it is difficult to clean the spaces between the tubes. When mechanical cleaning is required for the shell layer, a square arrangement is generally used to ensure a 6 mm cleaning passage. With the same baffle spacing, the flow cross-sectional areas of the equilateral triangular and concentric circular arrangements are larger than those of the other two arrangements, which helps to increase the flow velocity. The number of tubes arranged in a concentric circle pattern is greater than that in a triangular pattern, and the tubes are evenly distributed near the shell, making it difficult for the medium to take short circuits. In the refining industry, the square staggered arrangement (with a 45° corner angle) is still the most commonly used. Regardless of the arrangement, the distance between the wall of the outermost tube and the inner wall of the shell should not be less than 10 mm.