Looking for information on tubular air preheaters

This post was last edited by lupg on 2022-4-27 at 22:33. 1. The books on heating furnaces contain descriptions of the design aspects of tubular air preheaters, which are generally sufficient to meet the needs of technicians in engineering applications. 2. It is unknown to the original poster how in-depth their understanding of tubular air preheaters is, and it is therefore not possible to provide information that meets the requirement for “more detail”; the diagram below may represent the structure already known to them.

1. Are there calculations and designs for flow disruptors? I’ve seen some information stating that the flow disruptors are not welded to the heat exchange tubes; how are they then fixed? 2. Will fixing and welding the heat exchange tubes to the tube sheet cause the tube ends to crack or the tubes to burst due to excessive temperature differences? I’ve seen that some foreign drawings include expansions or bends in the design, but I haven’t found any relevant information on it.

Thermal expansion needs to be taken into account; since the pressure in the furnace flue is relatively low, the sealing required to compensate for the expansion displacement is relatively easy to handle. The schematic diagrams provided in the book are for reference only.

1. The original request of the poster has changed; they now want to understand the proprietary technologies related to air preheaters. 2. Turbulators, as elements used to enhance heat transfer, have been used in China for nearly 40 years, but the core technologies still remain in the hands of those involved in their development or of the product suppliers. As for whether there is a calculation method, as users we can only say sorry. Hoping that those skilled in technology have written monographs. 3 Perhaps our source of information is limited; a relatively useful figure we have come across is that the total heat transfer coefficient of the perturber light tube is 21.9 W/(m2.K). With the overall heat transfer coefficient, the heat exchange area can be determined. 4. The addition of perturbators may lead to vibrations; therefore, they should be fixed at the tube ends, either by welding or some other method. It is also possible to consider other solutions, but to ensure that vibration frequencies are avoided, computational analysis or experimental data are needed as a basis

Regarding the calculations after the use of baffles, a comparison table is provided here as follows: 1. Using an example from an article on the design of baffles in Fushun Petroleum Institute, all operating conditions remain unchanged except for the baffle settings; a general-purpose program is used to calculate the air preheater performance. 2. The baffle settings are divided into three scenarios: 2.1. The heat transfer coefficient inside the tubes is taken from the value given in the article’s example; 2.2. Baffles are used, and the program determines the heat transfer coefficient inside the tubes; 2.3. Tubes without baffles are used, with the program again determining the heat transfer coefficient inside the tubes. 3. Calculation results: 3.1. For scenario 2.1, the highest heat transfer coefficient inside the tubes was 75.5, resulting in a surplus capacity of 27.8% for the air preheaterAPH, which is consistent with the values shown in the article’s example. 3.2. For scenario 2.2, the heat transfer coefficient inside the tubes was 33.6, leading to a surplus capacity of -18.7% for the air preheaterAPH. 3.3. For scenario 2.3, the lowest heat transfer coefficient inside the tubes was 27.5, resulting in a surplus capacity of -29.1% for the air preheaterAPH

Thank you to this sea friend for their patient answers; the heat transfer coefficient is more or less the same. Many thanks! :)