The wear of tubes caused by flow induced vibration is one of the most significant factors that cause performance attenuation and malfunction of the heat exchanger.In this paper,aiming at the vibration caused by the non-uniform cross flow formed by the heat exchanger baffle,a visualized three-span 7x12 heat transfer tube bundle flow-induced vibration test facility is established.The acceleration data of the vibration in the first row of midspan tubes and the change data of the gap between the tubes and the support plate were obtained by the acceleration sensor in the tube and the visual vibration measurement by the high-speed camera,respectively,and the flow field between the tubes was obtained by numerical simulation.By comparing the experimental and simulation results of cross-flow-induced vibration of tubes under non-baffle mode and 2/3 gap baffle mode,it is shown that the velocity difference between the two structures after the third row of tubes is small,and the fluid elastic instability(FEI)critical velocity is similar,and the critical velocity of 2/3-gap baffle is slightly higher than that of the structure without baffle.By comparing five classical critical velocity relationships,it is found that Chen's correlation can conservatively predict the occurrence of instability.The visual test of the gap between the tube and the support plate shows that the two kinds of tubes with incoming flow structure are relatively stable against the hole on one side of the support plate at very low flow velocity.At a moderate flow rate,the tube reciprocates in the hole of the support plate with a large amplitude under the non-baffle mode,and slightly knocks,while in the non-uniform inflow structure,the tube still slides on the inner edge of the plum blossom hole on the support plate with a small amplitude.In the case of FEI,the non-baffle mode is mainly knocking,while the 2/3-gap baffle will obviously slide and knock.The 2/3-gap baffle is more prone to sliding wear between the heat transfer tube and the support plate,which will threaten the integrity of the heat transfer tube.
BaffleNonuniform flowVisualizationFlow induced vibrationTube baffle gap
维普
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