Problems in the calculation of heat exchanger diaphragms
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This post was last edited by cxd11888 on 2017-10-2 at 12:33. Example: For a floating-head heat exchanger with a nominal diameter of 700, the tube sheet type is a head-type tube sheet; the length of the tube sheet stub is 500 mm, and the corrosion allowance on the tube side is 2 mm. Question: 1. What are the lengths of sides a and b of the heat exchanger partition in the screenshot? (a Is it necessary to obtain the surface length of the head? ) 2. Should the corrosion margin be set at 2mm or 4mm? 3. How should the pressure difference on both sides of the split diaphragm be determined? 4. Additionally, why does the cross-sectional area of a stage partition appear when calculating the method for the rear cylinder? 5. For the data entry of the partition plates in the diagram, only data for one end of the partition plate can be entered. If there are four tube passes, how can data for the floating head partition plates be entered?
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None of the questions I raised have answers in the introduction on page P51 of GB/T151!
The partition is considered to suffer from bilateral corrosion, so the corrosion value should be 4. However, I haven’t updated to this version, so I don’t know if it will multiply by 2 by default. It depends on the calculation sheet.
When the three sides are fixed, a represents the inner diameter of the equipment, while b represents the axial length of the tube sheet partition; in other words, b includes the length of the end cap as well. Since b is directly proportional to the final thickness, it’s fine to use a larger value. In the case of multiple partitions, it’s necessary to determine a maximum thickness; in other words, calculations need to be done separately for each one. Because generally, the pressure difference acting on each chamber partition is different. As for how to calculate the pressure difference, it can be done in the same way as for heat transfer calculations; the calculation process shows the pressure difference at each stage. The total pressure difference can be considered as the pressure difference between the inlet and outlet of the tube side. There is a conservative formula for the pressure difference allocated to each stage. It seems to be based on how many times it has attenuated. I need to check again.
I don’t seem to have any memory of the forty-first one; is it only available in the latest version? I think it wasn’t included in my version. Let me take another look.
Regarding Article 4, it is new in the updated version of SW6; I checked the update list, and it seems to be used for calculating the reaction force of the gasket
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