Heat exchanger tube vibration
Heat exchanger tube vibration
(OP)
What is the best way to determine the vibration of tubes in a shell and tube exchanger. Is just monitoring vibration on the shell external wall gives a valid data? What is the normal vibration figure and the max allowable. If you guys have any experience in this, appreciate any sharing of ideas.
Thanks
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RE: Heat exchanger tube vibration
RE: Heat exchanger tube vibration
hfzmm - We have performed several field investigations of large heat exchangers. Tests we have used include impact tests of the tubes while the unit is down, strain gages inside the heat exchanger while the unit is running, and pressure measurements.
Impact tests will tell you if there are potential modes of concern. The main reason you care about tube vibration is if it causes high stress, cracks, and failures. The strain gages will help identify these problems.
We have observed that at various flow conditions, acoustic modes will be excited. Vortex shedding is usually the cause, but an acoustic mode can significantly amplify the pressure pulsation, which can be measured with pressure transducers.
The big problems occur when mechanical and acoustic natural frequencies are coincident. For more information on high frequency acoustic modes you may download the following paper at
http://www.engdyn.com/download/84.pdf
RE: Heat exchanger tube vibration
Agree with other posts, you are not going to get meaniful data from external measurements, however, if you have external noise and/or vibration then you may have a problem in the tube-bundle.
Blevins and varous heat exchanger authorities such as the ASME and the Heat Exchanger Inst. have design guidelines for avoiding tube bundle resonances.
It is not a simple or straight forward process. Your supplier is a good starting point.
Good luck,