Fluid Structure Interaction of Involute Fuel Plates in the High Flux Isotope Reactor Using a Fully-coupled Numerical Approach

This dissertation describes a fully-coupled (FC), finite-element (FE) based, algorithm for modeling and simulation of the fluid-structure interaction (FSI) of involuteshaped fuel plates used in research reactors; specifically the High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL). Following a graded approach to code and model validation, a cylinder in cross-flow benchmark is used to establish flow physics as well as properly coupling the FSI phenomena with increasing complexity. As an interim step toward HFIR LEU fuel plate simulations, three experiments are used for validation. The first, performed by Smissaert, is used to envelope large plate deflections and understand the validity of various fluid boundary conditions for single plate comparisons. Continuing with Smissaert's data, a 5-plate simulation is presented showing the first-ever multi-plate simulation using this FC and FE approach. Second, a vibrating plate, presented by Liu et al., is simulated showing the same technique to encompass self-excited, periodic plate deflections. Lastly, an experiment for the conceptual Advanced Neutron Source Reactor (ANSR) using involute plates is utilized to validate the ability of this FC and FE algorithm to predict the deflections of the involute-shaped plates used in the HFIR. The method shown herein accurately captures the established `S-shaped' deflection of the first mode of the involute plate providing guidance that researchers and designers can utilize in the forthcoming design of the next generation of low-enriched uranium (LEU) fuel plates for the HFIR. A `Lessons Learned' section which describes external routine coupling, geometry and meshing guidance, and solver settings used in the computational platform used to perform these FSI simulations is also provided.