An experimental investigation of fluid-elastic instability for a single row of tubes subjected to two-phase cross flow.

Abstract

Interesting features, connected with fluid-elastic vibration of tube bundles in a cross flow, have been reported in many papers. Most of the experiments were done for single-phase (liquid or air) flow. This paper presents an experimental investigation on vibrations of a row of five circular tubes with P/D =1.33, subjected to single-phase water and two-phase (air-water) cross flow. Experiments covered mass-damping parameters from 0.9 to 5 by changing the damping ratio. Experimental results show differences in characteristics of vibration response between those for pure water and two-phase flows. Depending on conditions specified by mass-damping parameters, void fraction and reduced flow velocity, air bubbles contained in the flow destabilize the vibrations of the row of tubes or they suppress the vibrations. Further, critical flow velocity for two-phase flow induced fluid-elastic vibration has been made clear for mass-damping parameters ranging from 0.9 to 5.