Numerical simulation research on the fluid-solid coupling characteristics of the lifting pipe under the influence of internal fluid
In order to research the vibration characteristics of the lifting pipe under the effect of internal flow,the fluid-solid coupling finite element model including the lifting pipe,the intermediate warehouse and the internal flow field is established according to the similarity theory,and the modal frequency of the lifting pipe under the effect of the internal flow field is calculated,and the harmonic response analysis carried out according to the cal-culation results.The effects of wall thickness,inner diameter,constant internal flow velocity,pulsating internal flow velocity with different frequencies and amplitudes on the vibration characteristics,especially the resonance behavior of the lifting pipe system are investigated.The results show that the frequency of the vibration displace-ment of the lifting pipe is consistent with the resonance frequency(12th order natural frequency)with the largest amplitude at a constant internal flow velocity,and the vibration is mainly longitudinal.Within 10％of the pipe length near the intermediate warehouse,the change in vibration amplitude of the lifting pipe is less than 5％.Compared with adjusting the inner diameter while keeping the wall thickness unchanged,adjusting the wall thickness while keeping the inner diameter unchanged has a more significant inhibition effect on the resonance behavior of the lifting pipe.When the amplitude of pulsating internal flow is greater than 0.5 m/s,the maximum vibration displacement and equivalent stress of the lifting pipe increase linearly.With the increase of the frequen-cy of pulsating internal flow,there is a resonance band with a width of 8 Hz centered on the 12th order natural frequency.Within the resonance band,the maximum equivalent stress of the lifting pipe appears at the top and gradually decreases along the water depth direction.
lifting pipefluid-structure interactionresonance responsefinite element analysis
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