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Title: Experiments on fluidelastic vibrations of tube arrays

Technical Report ·
DOI:https://doi.org/10.2172/7257504· OSTI ID:7257504

The overall objective of the activity is to develop new and/or improved, experimentally-validated analytical methods and guidelines for designing LMFBR components to avoid detrimental flow induced vibration. Many reactor system components, such as heat exchanger tubes and reactor fuel pins are susceptible to flow induced vibration. Due to fluid coupling, the tubes will respond in one or several of coupled modes. Therefore, understanding the coupled modes is essential in design to avoid detrimental flow-induced vibrations. Four series of tube arrays are tested. The arrangements of the tubes are as follows: (a) a row of five tubes with the gap to tube radius ratio (G/R) equal to 2.0, 1.0, and 0.25; (b) three-tube arrays in the staggered arrangement with G/R equal to 2.0, 1.0 and 0.5; (c) seven-tube arrays in the staggered arrangement with G/R equal to 1.5, 1.0 and 0.4; and (d) four-tube array in a square pattern with G/R = 0.5. The fourth series is tested under five different conditions: (1) fully submerged in unconfined water; (2) partially submerged in water; (3) near a flat wall; (4) contained in a circular cylinder; and (5) fully submerged in a liquid of high viscosity (mineral oil). A means to excite the tubes is provided by an electromagnetic exciter assembly. A servo system can be used to control input. Response in the form of tube acceleration is measured using two accelerometers mounted on each tube. The data is processed in a fast Fourier Transform Analyzer. An analysis is made for each test case. The detailed information for uncoupled and coupled natural frequencies, mode shapes, damping, and tube response are presented in the report. The experimental data and analytical results are found to be in good agreement.

Research Organization:
Argonne National Lab. (ANL), Argonne, IL (United States)
DOE Contract Number:
W-31-109-ENG-38
OSTI ID:
7257504
Report Number(s):
ANL-CT-77-16; TRN: 77-012964
Country of Publication:
United States
Language:
English