A single flexible tube in a rigid array as a model for fluidelastic instability in tube bundles

作者：Khalifa Ahmed^*; Weaver David; Ziada Samir

来源：Journal of Fluids and Structures, 2012, 34: 14-32.

DOI：10.1016/j.jfluidstructs.2012.06.007

• Flow-induced vibrations
• Fluidelastic instability
• Single flexible tube
• Tube arrays
• Heat exchanger

Fluidelastic instability is considered the most critical flow induced vibration mechanism in tube and shell heat exchangers, and as such has received the most attention. The present study examines the concept of using a single flexible tube in a rigid array for predicting fluidelastic instability. The experimental work published in the open literature involving the use of a single flexible tube in a rigid array is critically reviewed. Based on this, an experiment is designed to facilitate precise control of the system parameters and to study tube response at different locations in the array. Experiments were conducted using a fully flexible array as well as a single flexible tube in the same rigid array. It is found that a single flexible tube located in the third row of a rigid parallel triangular array becomes fluidelastically unstable at essentially the same threshold as for the fully flexible array. However, when the single flexible tube is located in the first, second, fourth, or fifth rows, no instability behavior is detected. Thus, tube location inside the array significantly affects its fluidelastic stability behavior when tested as a single flexible tube in a rigid array. It is concluded that, in general, fluidelastic instability in tube arrays is caused by a combination of the damping and stiffness mechanisms. In certain cases, a single flexible tube in a rigid array will become fluidelastically unstable and provide a useful model for fundamental research and developing physical insights. However, it must be cautioned that this behavior is a special case and not generally useful for determining the stability limit of tube arrays.

• 出版日期2012-10