Bazin, M. Gildas (2024) Instabilities in drag direction of steam generator tubes PRE - Research Project, ?? - ??.
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Abstract
Steam generator tube wear is a complex subject, particularly because of the fluid-structure interaction involved. Almost all the calculations carried out at present neglect the fluid-elastic coupling in the drag direction. The aim of our study is to observe what happens in this direction to see whether taking it into account in the calculations modifies tube wear or whether it is a negligible phenomenon. All our results come from simulations calculated with Castem, to which we have added the PANDA module. We model the vibrations of a straight tube fixed at its ends and subjected to a flow. Our study models turbulent forces %do you mean turbulent? and IFS ("fluid-elastic") forces and then observes their influence on the vibrations. For the IFS, we take the simple Connors-Axisa model, and our first task is to find the Connors constant for this model from existing data (we choose a value of 9). To try to be as faithful as possible to reality, we put two stops on our tube, representing anti-vibration bars (AVBs). We note that these AVBs drastically delay the onset of instability in the direction of drag thanks to the release of energy through friction and damping during contact. We also studied the influence of the clearance between the tube and these stops: the closer they are, the more the flow speed needs to be increased to observe the onset of instability. It is important to note that the turbulent force also plays a role in the onset of instability.
Item Type: | Thesis (PRE - Research Project) |
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Uncontrolled Keywords: | Direction de Traînée |
Subjects: | Materials Science, Mechanics and Mechanical Engineering |
ID Code: | 10066 |
Deposited By: | Gildas BAZIN |
Deposited On: | 02 sept. 2024 16:48 |
Dernière modification: | 02 sept. 2024 16:48 |
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