A Semi-Analytical Prediction Model for Fluid-Elastic Instability of a Normal Triangular Tube Array Under Transverse Flow Excitation

The heat exchange tubes in the steam generator are susceptible to vibration caused by fluid flow, which can lead to damage to both the tubes and their support structures due to collisions. To enhance the predictive accuracy and cost effectiveness of fluid-elastic instability mitigation, multiple models have been created to circumvent its occurrence.

In this research, a model has been developed to predict fluid-elastic instability in tube arrays by integrating Hassan’s time-domain-solving model with a parameter acquisition method using computational fluid dynamics (CFD) simulations. By utilizing CFD methods, a comprehensive set of tube-in-channel model parameters were acquired. This method eliminates the requirement of empirical parameters obtained through experiments. The acquired parameters were integrated into the time-domain, tube-in-channel model.

This model predicts fluid-elastic stability for a single flexible tube or a bundle of seven tubes within a rigid tube array, accounting for fluid forces in the lift direction. The stability map accurately represents the stiffness effect of flow-induced vibration, agreeing with experimental results and highlighting that the model may effectively utilize parameters obtained from CFD simulations. The combination of the time-domain-solving model and the CFD-based parameter acquisition method has been shown to produce a reliable model.