Basis for determining the baffle spacing

It is generally determined based on the requirements of the manufacturing process

According to GB151, the minimum spacing between baffle plates should generally be no less than one-fifth of the inner diameter of the cylinder, and also no less than 50 mm. . . . . .

The baffle spacing options are 100, 200, 300, and so on. What is the basis for making this choice? The determination of the baffle spacing (which is not really a matter of selection) is based on heat transfer calculations in the process. The factors that influence this determination include: 1. Reducing the baffle spacing in order to increase the heat transfer coefficient between the tubes, thereby raising the overall heat transfer coefficient K value； 2. Increase the spacing between baffle plates to reduce the flow velocity in the shell side, thereby lowering the pressure drop –Δp in that side; 3. Decrease the spacing between baffle plates to reduce the unsupported length of the heat exchange tubes, increasing their stiffness and preventing vibrations and similar issues. Generally, these three factors are considered together: it is necessary to meet the requirements regarding the heat exchange area (K value), as well as the requirement for pressure drop – Δp. Additionally, in mechanical design, the requirement concerning the unsupported length must also be satisfied. Therefore, heat exchanger design is a systematic process that requires taking into account various factors in order to determine the spacing between the baffle plates. When the process does not specify the baffle spacing, in our mechanical design we only consider meeting the unsupported length requirement.

Regarding the arc-shaped baffle 151, there’s another point to note: in order to make the flow velocities through the window and across the tube bundle equal to each other, it’s necessary to determine the appropriate spacing; moreover, the height of the notch also needs to be calculated

In response to the person above: The principle for determining the notch in the baffle should be to calculate the spacing between the baffles based on process considerations. Once the spacing is determined, it is necessary to calculate the flow area between two baffles, at the center of the shell side or near the center (in the case of partition plates). This area is calculated as the shell diameter (or chord length) multiplied by the baffle spacing, minus the area occupied by the heat exchange tubes; this area should be roughly equal to the area of the notch in the baffle (with the cross-sectional area of the heat exchange tubes also taken into account). For reference only