Numerical Simulation of the Fluid Elastic Instability of Concentric Arrays of Tube Bundles


Fluid elastic instability is the most important mechanisms that excite vibration of tube bundles in heat exchangers. The study on fluid elastic instability of concentrically distributed tube bundles can provide valuable guidance for the design, manufacture and maintenance of this type of heat exchangers. Based on the geometric characteristics of concentric arrays, three representative physical models were established, including quasi-square arrangement, transitional arrangement and quasi-triangle arrangement. Flow field and vibration characteristics were obtained from fluid-structure interaction numerical simulation of ANSYS CFX software. The critical velocity and main vibration direction at different positions of concentric arrays were analyzed. It was found that the main vibration direction changed from stream-wise direction to cross-stream direction as the gap flow velocity increased. In the three arrays, the maximum critical velocity appeared in the quasi-square arrangement area, whereas the minimum one occurred in the transition arrangement area. The simulation results show that the transition arrangement was easiest to appear unstable in the tube bundles of concentric arrays, which high attention should be paid to during the design and engineering application.

Pressure Vessel Technology