(Quiz time) What is the difference between a fixed-tube-sheet heat exchanger and a U-tube heat exchanger?

U-tube heat exchangers have no temperature difference stress

The tube sheet in a fixed-tube-sheet heat exchanger is subjected to greater stress than that in a U-tube heat exchanger

Fixed-tube-sheet heat exchangers: When there is a large temperature difference between the tube bundle and the shell, resulting in different rates of thermal expansion, it can cause the connection between the tubes and the tube sheet to fail, leading to fluid leakage； To avoid future problems, expansion joints can be installed on the shell; however, they can only reduce but not completely eliminate the thermal stresses caused by temperature differences. In U-tube heat exchangers, both ends of the tube bundle are fixed to the same tube sheet, while the bent end is not fixed, allowing each tube to expand and contract freely without being affected by other tubes or the shell ；

Fixed-tube-sheet heat exchangers: This type needs to be considered when there is a large temperature difference, as thermal expansion may cause the tubes to separate from the tube sheet. They are simple to manufacture and cost little. U-tube heat exchangers: The tubes have room to expand and contract freely, unaffected by other tubes or the shell; however, cleaning the tube side is difficult.

In fixed-tube-sheet heat exchangers, the tube sheets at both ends of the tube bundle are integrated with the shell; this results in a simple structure. However, such exchangers are suitable only for heat exchange processes where there is not a large temperature difference between the hot and cold fluids, and where mechanical cleaning of the shell side is not necessary. When the temperature difference is somewhat large and the shell-side pressure is not too high, elastic compensation rings can be installed on the shell to reduce thermal stress. In a U-tube heat exchanger, each heat exchange tube is bent into a U shape, with its two ends fixed to the upper and lower sections of the same tube sheet; the tube box contains partitions that divide the tube bundle into inlet and outlet chambers. This type of heat exchanger completely eliminates thermal stress, has a simpler structure than the floating-head type, but the tube side is difficult to clean.

The free floating at the tail end of the U-tube heat exchanger can eliminate temperature difference stress

This has been discussed before; I think the detailed differences in calculations should be based on the specifications in GB151. http://bbs.hcbbs.com/viewthread.php?tid=408752&highlight=%B9%CC%B6%A8%B9%DC%B0%E5%2BU%D0%CE%B9%DC The last edit to this post was made by wode*aohei on 2009-3-19 at 15:50.]

Fixed-tube-sheet heat exchanger: In a fixed-tube-sheet heat exchanger, the tube sheets at both ends and the shell are integrated together. When there is a large temperature difference between the two fluids, a compensating ring (or expansion joint) is welded in an appropriate position on the shell. When the shell and the tube bundle expand thermally at different rates, the expansion ring undergoes slow elastic deformation to compensate for the thermal expansion caused by temperature difference stresses. 　　Features: Simple structure and low cost; difficult to clean and maintain the shell side, and the material in the shell side must be clean and resistant to scaling. 　　A fixed-tube-sheet heat exchanger is mainly composed of components such as a shell, tube sheet, tube bundle, and head gasket. The structural feature of a fixed-tube-sheet heat exchanger is that a tube bundle is installed within the shell; the tubes at both ends of the tube bundle are fixed to the tube sheet by welding or expansion bonding. The tube sheets at both ends are directly welded to the shell, while the inlet and outlet pipes on the shell side are directly welded to the shell as well. The outer circumference of the tube sheet and the head flanges are secured together with bolts. The inlet and outlet pipes on the shell side are also welded to the head. Inside the tube bundle, several baffle plates are placed according to the length of the heat exchange tubes. The tube side of this heat exchanger can be divided into any number of sections using partitions. 　　Fixed-tube-sheet heat exchangers have a simple structure, low manufacturing costs, are easy to clean on the tube side, allow the tube side to be divided into multiple passes, and the shell side can also be divided into two passes; they come in a wide range of specifications, which is why they are widely used in engineering applications. Cleaning the shell side is difficult, and it is not suitable for use with dirty or corrosive media. When the expansion difference is large, expansion joints can be installed on the shell to reduce the thermal stress caused by the temperature difference between the tube and shell sides. 　　The characteristics of the fixed tube sheet heat exchanger are: 1. The bypass seepage is small ； 2. Low cost ； 3. No internal leakage ； 4. The disadvantage of the fixed tube sheet heat exchanger is that there is a large temperature difference between the shell and the tube walls, which leads to the generation of thermal stress. The shell side cannot be cleaned, and once the tubes corrode, the entire unit becomes unusable; as a result, its service life is short, and it is not suitable for applications where scaling occurs easily on the shell side. U-tube heat exchanger: In a U-tube heat exchanger, each tube is bent into a U shape; the fluid inlets and outlets are located on opposite sides of the same end. The shell is divided into two chambers using partitions, and each tube can expand and contract freely to address thermal compensation issues. 　　Features: Simple structure, light weight, suitable for high-temperature and high-pressure environments. It is difficult to clean the pipe train, and the fluid in the pipe train must be a clean material that does not tend to form scale.

That’s too explicit. Where can I find lecture materials on heat exchange equipment? Thank you! !