Numerical study on flow-induced vibration of LBE-cooled wire-wrapped rod bundle

Flow-induced vibration (FIV) characteristics of LBE-cooled wire-wrapped rod bundle are crucial to the wire-to-cladding fretting. In the present study, numerical simulation on FIV of wire-wrapped rod bundle in LBE flow was performed using a fluid–structure interaction methodology based on the coupling between fluid and solid domains. The effects of geometry parameters on the FIV of wire-wrapped single rod and rod bundle were obtained. The results show that the circumferential force of coolant on the single fuel rod was uneven, which made the fuel rod undergo elliptical and off-axis periodic vibration. The variations of structure parameters of wire spacers had weak effects on the vibration of the single rod, while significant effects on the vibration trajectory of rod bundle. The vibration characteristics of border rods were more sensitive to the variations of transverse flow, while the center fuel rods were more sensitive to the difference in support constraint.