Objective Steam generators, as critical components of reactor systems, are susceptible to severe structural damage from flow-induced vibrations (FIV) in heat transfer tubes and other components, significantly compromising operational safety. With the recent development of large-scale marine vessels and floating nuclear power plants, the application of steam generators under marine conditions has expanded. However, the swaying motion of carriers in oceanic environments introduces complexities into FIV mechanisms, posing heightened risks to equipment integrity. Therefore, conducting vibration analysis of steam generator tubes under swaying conditions is essential to elucidate marine-specific FIV mechanisms and provide insights for safety design and mitigation strategies.

Method Taking the straight tube segments in steam generators as the research objects, the stress, strain, and flow field characteristics under varying swaying conditions were numerically simulated using a one-way fluid-structure coupling approach. The results were compared with those under no oscillation conditions to study the influence mechanism of oscillation conditions on the flow induced vibration parameters of the heat exchange tube. Comparative analyses with non-swaying scenarios were performed to investigate the influence of swaying on FIV parameters.

Results The results demonstrate that under swaying conditions, the drag coefficient of heat transfer tubes exhibits periodic fluctuations synchronized with the swaying period. Total deformation and equivalent stress in the tubes increase significantly compared to static conditions. Furthermore, the lift and drag coefficients exhibit complex frequency-domain fluctuations, with frequency-domain amplitudes amplifying proportionally to sway angles.

Conclusion The fluid-structure interactions near the heat transfer tubes intensify under marine conditions, leading to aggravated vibrations and elevated risks of safety incidents. These findings underscore the necessity for stringent design criteria and enhanced vibration suppression measures to ensure the safe operation of steam generators in oceanic environments.