As the name implies, baffles are plates used to change the flow direction of fluids. They are often used in the design of shell-side medium flow channels of shell-and-tube heat exchangers. The number of baffles is determined according to the properties and flow rate of the medium and the size of the heat exchanger. Baffles are set in the shell side, which can not only improve the heat transfer effect, but also support the tube bundle. There are two types of baffles: arched and disc-circular. There are three types of arched baffles: single arched, double arched and triple arched. The types are as shown in the figure below:

The height of the notch of the arched baffle should make the flow rate of the fluid passing through the notch similar to that when crossing the tube bundle. The size of the notch is determined by the percentage of the cut-off bow chord height to the inner diameter of the cylinder. The notch of the single arched baffle is shown in the figure. The notch chord height h value should be 0.2~0.45 times the inner diameter of the cylinder. The notch of the arched baffle can be cut below the center line of the tube row as shown in the figure, or cut between the small bridges of the two rows of tube holes.