STV-9 Review of Two-Phase Flow-Induced Vibration in Heat Exchangers
Flow-induced vibration can be a serious problem in shell-and-tube heat exchangers. When the flow in a heat exchanger's secondary side interacts with the array of tubes containing the primary fluid, tube vibration inevitably occurs. Excessive vibration can cause tube failures from fatigue or fretting wear. The problem is especially critical in nuclear steam generators, where safety and reliability are of foremost concern.
This report presents an overview of flow-induced vibration in tube bundles and describes axial-flow and crossflow-induced vibration under single-and two-phase flow conditions. Vibration mechanisms and dynamic forces acting on the vibrating structure are examined, and the state of the art is summarized. Based on the findings of this work, research is required in the following areas to more accurately characterize two-phase flow-induced vibration in shell-and-tube heat exchangers:
- two-phase flow field
- added mass and damping in two-phase flow
- two-phase fluid excitation forces
- tube response and local two-phase flow parameters
The report also reviews current HTRI vibration analysis methods and offers specific recommendations for improvement. Given that two-phase flow inside a tube bundle is usually well separated, we suggest a modification of HTRI's present homogeneous flow model for two-phase flow-induced vibration analysis that incorporates these findings.