Flow-Induced Vibration Model for Steam Generator Tubes in Two-Phase Flow Available to Purchase

While steam generators operate in two-phase flow, the complex nature of the flow makes the prediction of flow-induced fluidelastic instability of steam generator tubes a challenging problem yet to be solved. In the work reported here, the quasi-static fluid force-field, which is the important unknown for two-phase flows, is measured in a rotated-triangle tube bundle for a series of void fractions and flow velocities. The forces are shown to be strongly dependent on void fraction, flow rates and relative tube positions. The fluid force field is then employed along with quasi-steady vibration stability models, originally developed for single phase flows, to model the two-phase flow problem and predict the critical instability velocity. The results are compared with dynamic vibration stability tests and are shown to be in good agreement. The present work uncovers some of the complexities of the fluid force field in two-phase flows. The database provides new potential to designers to estimate expected fluid dynamic loads under operating conditions. The force field data may also be applied in dynamic computations for tube wear simulations, replacing the simple Connors’ model which is currently used.