Session: 3.4 - CFD for Nuclear Thermal Hydraulics

Paper Number: 156138

156138 - Toward Modeling of Fusion Fluid Blanket Flows Using the Spectral Element Method 

Abstract: 

Accurately modeling flow and heat transfer is essential for the development of fusion reactors. This study focuses on validating experimental data from a differentially heated cavity using NekRS, a high-fidelity spectral element fluid dynamics code. The experimental setup, designed to replicate buoyancy-driven flows in fusion reactors, consists of a fluid volume enclosed between two vertical walls: one heated with a constant thermal flux and the other passively cooled. Temperature measurements were recorded using thermocouples placed on the interior surfaces of the walls at the midpoint of the fluid column. Previous research validated these experimental results using Reynolds-Averaged Navier-Stokes k-ϵ simulations in ANSYS Fluent. However, these simulations were limited in their ability to resolve complex, three-dimensional flow interactions. Large Eddy Simulations address these limitations by calculating larger turbulent structures directly and smaller scales using a sub-grid model. Compared to a Reynolds-Averaged Navier-Stokes k-ϵ simulation, this is a more computationally expensive method of solving the Navier-Stokes equations with higher fidelity. This work employs Large Eddy Simulations in NekRS, modeling three-dimensional Rayleigh-Bénard convection with conjugate heat transfer. In addition to the cavity results, this work presents Large Eddy Simulation results for the CHIMERA facility, a state-of-the-art experimental setup for studying fusion breeding blankets. The inclusion of CHIMERA results highlights NekRS's capability to provide high-fidelity simulations for complex fusion reactor systems.

Presenting Author: Logan Hiland Pennsylvania State University

Presenting Author Biography: I aim to use my background in mechanical engineering and nuclear engineering to accelerate the development of advanced reactor technology.