Flow Induced Vibration of Shell & Tube Type Heat Exchanger (2nd Report, Confirmation of Countermeasures)

Abstract

This paper describes the confirmation of countermeasure's effect for flow-induced vibration in a shell & tube type heat exchanger. This type of heat exchanger has often been used in the LPG gas carrier ship and has sometimes caused a fretting and finally comes to a fatigue failure. In flow-induced vibration, there are vortex-induced vibration, fluid elastic instability and buffeting. In this paper, the clip is adopted as the countermeasure and it is clarified that the clip can suppress the tube vibration drastically. In this experiment, another countermeasure, that is to say, the dummy tube array is also examined. However the fluid elastic instability occurs by use of dummy tube array. The reason is that the dummy tube was supported by baffle plates without clearance. Therefore the damping ability becomes very small and the natural frequency of the tube appears very clearly.