cryogenic bending/bowing of LNG rundown lines
cryogenic bending/bowing of LNG rundown lines
(OP)
Any body in the group had experience in considering cryogenic bending/bowing in their stress analysis of LNG rundown lines. This is the phenomena in which during the period when horizontal pipe lines are partially filled with LNG, a temperature differential from top to bottom of the pipe would occur. This then leads to extra stresses on the elbows of pipes. I would appreciate if you could share to me the method how did you calculate the stresses involving cryogenic bending/bowing. How can you determine for the differential temperature from top to bottom of pipe.
Thank you in advance.
jim0210
Thank you in advance.
jim0210





RE: cryogenic bending/bowing of LNG rundown lines
Please explain for us how you have a "horizontal pipe lines are partially filled" By partially filled you mean part liquid (LNG) and part vapor (NG). How is this possible?
PennPiper
RE: cryogenic bending/bowing of LNG rundown lines
Thanks,
jim0210
RE: cryogenic bending/bowing of LNG rundown lines
Best regards
pennpoint
RE: cryogenic bending/bowing of LNG rundown lines
Besides selecting the right material for your pipe, if you're trying to come up with analytical solutions to the stresses developed across the section, the only way to go is by Finite Element Analysis method or a FEA software. "FEPIPE" is one that is costumized for pipe stress analysis. A software like "CAESAR II" won't help you here, because it considers the pipe as beam elements and performs the stress calcs based on beam equations. Or you can go with an all purpose FEA software like "ANSYS". I guess it depends which one is easier for you to get a hold of.
good luck
drno
RE: cryogenic bending/bowing of LNG rundown lines
L.C. Peng wrote this papaer and it may be useful to this discussion:
http://www.pipestress.com/papers/Therm-Insul.pdf
Regards, John.
RE: cryogenic bending/bowing of LNG rundown lines
Thanks again
jim0210