Numerical study on fluidelastic instability of tube bundles in two-phase flow considering the effect of tube boundary constraint

This paper investigates fluidelastic instability of a tube array in two-phase crossflow considering the effects of tube constraint conditions. We first established a theoretical model of tube bundles subjected to two-phase flow. Then, we wrote a numerical calculation program and verified the validity. The following three types of boundary constraints of the tube bundles were concerned in this study: cantilever, simply-supported, and fixed-end tube bundles. We calculated the eigenvalues, the critical velocities, and the instability modes of these three types of tube bundles within the void fraction ranging from 0% to 80%. The results show that the tube constraint conditions could change the critical velocity of the tube bundles, while may not affect the critical reduced velocity and the fluidelastic instability factor of the Connors equation. It is also found that the structural boundary constraint could not change the instability mechanism of the tube bundles in two-phase crossflow. (C) 2020 Elsevier Ltd. All rights reserved.