116 A Measurement of Gap Flow Velocity Regarding the Evaluation of Fluid-Elastic Vibration of Tube Bundle : A Measurement Example for Tube Bun dle in Mixed Parallel and Cross Flow

Abstract

Tube bundles are used in heat exchangers and inner reactor components, and the flow field around the tube bundles contains cross and parallel flow components. Fluid-elastic vibration should be evaluated for tube bundle in the flow with the cross flow component. When critical velocity of fluid elastic vibration is evaluated for the tube bundle in the mixed cross and parallel flow, the parallel flow hardly affects the vibration characteristics, and normally only cross flow is taken into account. However, very few studies were conducted to evaluate the flow velocity distribution of mixed cross and parallel flow. In this study, water tunnel tests under mixed parallel and cross flow conditions were preformed to understand the influence of the balance of parallel and cross flow component on vibration response. It was found that the critical flow velocity for self-excited vibration was not influenced by parallel flow component, and depended only on the cross flow component.