Investigation on mechanism of flow induced vibration of spiral tube bundle in cross lead bismuth flow

Abstract

BackgroundThe flow induced vibration of spiral tube bundle widely exists engineering practice. The traditional fluid medium is water and air, whilst lead bismuth fluid has gradually become a new heat exchange medium in recent years.PurposeThis study aims to analyze the flow induced vibration of single row tube bundle in cross lead bismuth flow.MethodsThe computational fluid dynamics (CFD) analysis code FLUENT and the finite element analysis code ANSYS were used to simulate the flow induced vibration of a single row spiral tube bundle. The flow field profile and structural response at different times were analyzed respectively, and the corresponding relationship between the flow field change and structural vibration was explored. The physical insight into the flow induced vibration of the tube bundle was provided.Results & ConclusionsSimulation results show that the vortex shedding occurs in the single row tube bundle in the cross lead bismuth, and the frequency of vortex shedding increases with the increase of the flow velocity. Due to the interference of vortex shedding between the pipes, the vibration frequency of the middle pipe is mainly two times of vortex shedding frequency, while the vibration response of the pipes on both sides is dominated by the vortex shedding frequency, accompanied by a small frequency doubling. With the increase of the flow velocity, the influence of the interference between pipelines on the frequency doubling vibration response of pipeline vibration is gradually weakened. When the inlet velocity exceeds a certain value, the amplitude of the pipe increases suddenly, causing fluid-elastic instability of the pipelines.

Keywords

• spiral tube bundle
• flow-induced vibration
• lead bismuth fluid
• vortex shedding
• fluid-elastic instability