Problem:
The following Error message appears when running the program:
518 - Tubesheet: the gap (4.179 mm) between the shell (tube side) and OTL is not sufficient to take into account the knuckle radius (10 mm).
How to avoid this error.
Solution:
This error occurs when the available radial gap between the Shell Internal Diameter (ID) and the Outer Tube Limit (OTL) is smaller than the required knuckle radius.
From the provided example (see image above):
-
- Shell ID = 672 mm
- Outer Tube Limit (OTL) = 663.643 mm
- Knuckle Radius = 10 mm
The gap is calculated as: (Shell ID – OTL) / 2 = 4.179 mm
Since 4.179 mm < 10 mm, the available clearance is insufficient to accommodate the knuckle radius, resulting in the error.
Recommended Actions
Modify the tube layout to increase the available gap by:
-
- Reducing the Outer Tube Limit (OTL):
- Decrease the number of tubes
- Adjust tube pitch or layout pattern
- Increasing the Shell Internal Diameter (ID) (if design permits)
- Reviewing Tubesheet geometry assumptions
- Reducing the Outer Tube Limit (OTL):
See Also