How AutoPIPE Vessel calculates number of tubes/shell ID in Heat Exchanger?

There are three ways of determining the number of tubes/shell ID. Any of the following works:

1. Enter number of tubes. In this case, the program automatically calculates the OTL and Internal Diameter from the design information available (e.g., number of tubes, tube pitch, pitch type etc.).
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2. Specify Outside Tube Limit or OTL. In this case, the program automatically calculates the number of tubes that can be accommodated from the design information available (e.g., OTL, tube pitch, pitch type etc.).
   OR
   
   
3. Specify Internal Diameter. In this case, the program automatically calculates the number of tubes that can be accommodated from the design information available (e.g., Internal Diameter, tube pitch, pitch type etc.).

If the number of tubes is specified, do not enter OTL or Internal Diameter information as the same will be automatically calculated.
Likewise, if OTL or Internal Diameter is specified, do not enter number of tubes information as the same will be automatically calculated.
If both tube number and internal diameter are entered for some reason, the larger of the possible values will govern, see the example below:

Example :
The number of tubes=600 cannot be accommodated inside a shell with internal diameter=300 hence the number of tubes is maintained as in the image below (Note that it may not be possible to exactly match number of tubes due to geometry constraints. In this example here the input number of tubes = 600 but the program calculates the total number of tubes = 603 which is slightly more, in this case the user needs to adjust manually by eliminating some tubes to make the number of tubes = 600).

Keeping the tube number=600 the Internal Diameter is now increased to 900, observe that the shell ID is now maintained as 900 but the number of tubes have been increased to 925 to occupy the extra space created due to internal diameter increase hence the tube number as 600 is NOT maintained.

NOTE: If the user is entering a value in this field, then the program automatically calculates the shell component dimensions including internal diameter, so it is advisable that the user do not enter the shell internal diameter in the shell component properties dialog box.