Pipe Stress due to Thermal Expansion
Pipe Stress due to Thermal Expansion
(OP)
I have a stainless steel pipe system that runs about 35' along the x-axis and then 10' along the y-axis. The system is fixed at both ends. The working fluid is air, and temperature goes from 50F to 300F.
The system experiences thermal expansion due to the temperature increase. I have calculated this expansion to be about 0.83 inches in x-axis, and .21 inches in y-axis. I am using ASME B31.3 to analyze the stresses within the system.
I am however having a problem determining the in-plane, out-of-plane, and torsional moments for the bending stresses. Any guidance on how to determine these values would be greatly appreciated. It seems fairly simple but am at a loss. Thanks
The system experiences thermal expansion due to the temperature increase. I have calculated this expansion to be about 0.83 inches in x-axis, and .21 inches in y-axis. I am using ASME B31.3 to analyze the stresses within the system.
I am however having a problem determining the in-plane, out-of-plane, and torsional moments for the bending stresses. Any guidance on how to determine these values would be greatly appreciated. It seems fairly simple but am at a loss. Thanks





RE: Pipe Stress due to Thermal Expansion
RE: Pipe Stress due to Thermal Expansion
mxms80809, C2it is referring you to "the classics" of piping design and these are all worth finding and reading. You can also download (for free) this file which will give you the pertinent section of the olde "Grinnell" book mentioned by C2it:
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Regards, John.
RE: Pipe Stress due to Thermal Expansion
It took me a while to find the suggested reading material, but I did find the Design of Piping Systems (extremely old) and Piping Handbook. Unable to locate the others. The ones I did get are valuable resources, Lots of great information.
I have evaluated my system and have established a max Se= 34,000psi which is over the allowable Sa= 32,650psi. Looks like i need to add an expansion joint, and determine guides. Does anyone have any helpful hints when it comes to expansion joints?
RE: Pipe Stress due to Thermal Expansion
You do not "NEED" an expansion Joint.
What you need is more flexibility in your current routing.
Example:
Your current design "runs about 35' along the x-axis and then 10' along the y-axis.
If you have the room I suggest that you try the following"
Run 30 feet in the x-axis turn in the opposite direction as before and run 6 feet then turn in the original direction and run 5 feet then turn and run 16 feet to your end point.
This will give you a more flexible configuration and may be below your stress allowable.
It will be cheaper than the expansion joint and it eliminates the possible of a weak point in the system in the future.
RE: Pipe Stress due to Thermal Expansion
RE: Pipe Stress due to Thermal Expansion
http://virtualpipeline.spaces.msn.com
"What gets us into trouble is not what we don't know, its what we know for sure" - Mark Twain
RE: Pipe Stress due to Thermal Expansion
Would it be unwise to say that if you stepped this line, depending on support availability, that you would lessen the stress at more points and still have functionality. Proceeding 15' on x then 5' on y then 15' on x and finally 5' on y. I would only suggest this because it doesnt seem possible to put in a simple swing joint on the z axis.
Your comments would be appreciated since I too would like further information on this subject.
Regards,
RE: Pipe Stress due to Thermal Expansion
RE: Pipe Stress due to Thermal Expansion
Thanks
RE: Pipe Stress due to Thermal Expansion
y +10 connection, 90 to x, (attach flange on x at elbow), insert metallic bellows, (attach flange on x), x +35 connection.
With this type of connection you would get both sets of deflections at one point.
Hope this might help. As for locating the metallic bellows I can not help for I do not know the manufacture that my client uses.
Regards
RE: Pipe Stress due to Thermal Expansion
RE: Pipe Stress due to Thermal Expansion
Thanks
RE: Pipe Stress due to Thermal Expansion