Investigation of surface texturing for enhancing the anti-vibration support structure of heat exchanger tubes

Flow-induced vibration (FIV) often causes wear between heat exchanger (HE) tubes of steam generators (SGs) and their support structures, such as anti-vibration bars (AVBs), which in turn compromises the structural integrity and operational safety of the nuclear power system. To mitigate this issue, this study proposes the use of laser surface texturing (LST) to enhance the wear resistance of AVBs. Micro-textures with different geometries and area densities are fabricated on AVB surfaces using femtosecond laser processing. Series of impact-wear tests are conducted in both water and air environments to simulate friction process under actual operating conditions. The results indicate that the water environment not only effectively suppresses stress but also extends the wear location along the axial direction of the HE tube, preventing the wear depth from rapidly penetrating the tube wall thickness. The primary wear mechanisms in the water environment are identified as fatigue wear and oxidative wear, differing from the fatigue-abrasive composite wear mechanism observed in air. A conversion method for wear volume between the two environments is also established. This study confirms that surface texturing is an effective method for extending the lifespan of HE tubes and enhancing their structural integrity.