Numerical Investigation of Flow-Induced Vibration and Fretting Wear Potential of Multi-Span U-Tubes with Clearance Supports
NURETH-14 - 2011 September 25-30


Presented at:
NURETH-14
2011 September 25-30
Location:
Toronto, Canada
Session Title:
A7-1 Mini Symposium on Flow-induced Vibration in Nuclear Components

Authors:
Marwan Hassan (University of New Brunswick)
Atef Mohany (University of New Brunswick)
  

Abstract

In this paper, a numerical model is developed to predict the non-linear dynamic response of a

steam generator mutli-span U-tubes with Anti-Vibration Bar (AVB) supports and the associated

fretting wear

due to fluid excitations. Both the crossflow turbulence and fluidelastic instability

forces are considered in the model. The finite element method is utilized to model the vibrations

and impact dynamics.

The tube bundle geometry is similar to the geometry used in CANDU®

steam generators.

Eight sets of flat bar supports are considered. Moreover, the effect of

clearances between the tubes and their supports, and axial offset between the supports are

investigated. The results are presented and comparisons are made for the parameters influencing

the fretting-wear damage such as contact ratio, impact forces and normal work rate. It is clear

that the tubes in loose flat-bar supports have complex dynamics due to the possible combinations

of geometry

, tube-to-support clearance, offset, and misalignment. However, the results of the

numerical simulation along with the developed model provide new insight into the flow-induced

vibration mechanism and fretting wear of multi-span U-tubes that can be

incorporated in future

design guidelines of steam generators and large heat exchangers.

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