A review of cross-flow induced vibrations in heat exchanger tube arrays

This paper provides a brief overview of progress in our understanding of flow-induced vibration in power and process plant components. The flow excitation mechanisms considered are turbulence, vorticity shedding, fluidelastic instability, axial flows, and two-phase flows. Numerous references are provided along with suggestions for future research on unresolved issues.

Flow-Induced Vibrations in Power and Process Plant Components—Progress and Prospects

This paper is the second part of the two-part review article presenting an overview of mechanics of pipes conveying fluid and related problems such as the fluid-elastic instability under conditions of turbulence in nuclear power plants. In the first part, different types of modeling, dynamic analysis and stability regimes of pipes conveying fluid restrained by elastic or inelastic barriers were described. The dynamic and stability behaviors of pinnedpinned, clamped-clamped, and cantilevered pipes conveying fluid together with curved and articulated pipes were discussed. Other problems such as pipes made of viscoelastic materials and active control of severe pipe vibrations were considered. The first part was closed by conclusions highlighting resolved and nonresolved controversies reported in the literature. The second part will address the problem of fluidelastic instability in single- and twophase flows and fretting wear in process equipment, such as heat exchangers and steam generators. Connors critical velocity will be discussed as a measure of initiating fluidelastic instability. Vibro-impact of heat exchanger tubes and the random excitation by the cross-flow can produce a progressive damage at the supports through fretting wear or fatigue. Antivibration bar supports used to limit pipe vibrations are described. An assessment of analytical, numerical, and experimental techniques of fretting-wear problem of pipes in heat exchangers will be given. Other topics related to this part include remote impact analysis and parameter identification, pipe damage-induced by pressure elastic waves, the dynamic response and stability of long pipes, marine risers together with pipes aspirating fluid, and carbon nanotubes conveying fluid. DOI: 10.1115/1.4001270

Mechanics of Pipes Conveying Fluids—Part II: Applications and Fluidelastic Problems

A generalization of the quasi-steady theory is proposed, the aim of which is to model the most important unsteady effects neglected by the conventional quasi-steady assumption. Although this generalized model, referred to as the quasi-unsteady model, can be applied in a vast range of flow-induced vibration problems, including classical aeroelasticity, it was primarily developed to improve the theoretical prediction of the fluidelastic behaviour of a single flexible cylinder positioned in the midst of an array of rigid cylinders. In this context, it is shown that the previous improvement to the quasi-steady theory proposed by Price & Paidoussis can be considered as a particular case of the quasi-unsteady model. Results obtained with the quasi-unsteady model are compared to experimental data and to solutions from the Price & Paidoussis model; both modal parameter variation with flow velocity and stability diagrams are considered. This comparison shows that the quasi-unsteady model is a clear improvement on Price & Paidoussis’ approach, leading to a more reasonable agreement with experimental results and providing refined insights into the physical mechanisms responsible for fluidelastic instability.

J.H. Lever

Papers

On the stability of heat exchanger tube bundles, part I: Modified theoretical model

On the stability of heat exchanger tube bundles, part II: Numerical results and comparison with experiments