Fluidelastic and Vortex Induced Vibration of a Finned Tube Array

Abstract

Fluidelastic and vortex induced vibration are important problems in operating heat exchangers. Many studies have been conducted to solve the problems. As a result, design guideline has already existed for the flow-induced vibration of a tube bundle. On the other hand, some kinds of heat exchanger use finned tube array in order to improve the efficiency of the heat transfer. For finned tube array, some studies for vortex induced acoustic resonance have been conducted, where Strouhal numbers are obtained. However fluctuating lift coefficients due to vortex are important from the viewpoint of tube vibration. Moreover, critical velocities for fluidelastic vibration are also important. In this study, fluidelastic and vortex induced vibration tests were conducted for a triangular finned tube array. Two different frequencies of the vortex shedding were observed. For this tube array, Strouhal numbers were 0.13–0.15, 0.37–0.39. However vortex induced forces were too weak to excite the finned tubes. For this tube array, averaged Connors’ constant K was 6.8.